Our editors pick the products & services we write about. When you buy through our links, we may get a commission. Learn more.

OBD1 Code Lists With Meanings/Fault Location

There is absolutely one thing that every vintage car owner has in common: The hardships of diagnosing car troubles, especially OBD1 diagnostic trouble codes. And the differences in the OBD1 code lists and other parts make it even harder.

There are maybe a few of the questions that may be running through your head when your car starts acting up.

  • “How do I find out what is wrong with my car?”
  • “What are OBD1 codes?”
  • “Do I need a mechanic
  • “Are the OBD1 diagnostic trouble codes universal or manufacturer specific?”
  • “What does this OBD1 code mean?”

Do not worry!! In this article, you will understand what are the differences and get some lists of OBD1 code from different brands with meaning/fault locations.

What Are OBD1 Codes?

OBD is short for On-Board Diagnostics, an automobile term used to refer to a computer that monitors your engine through a series of sensors in order to track and regulate the performance of your car.

OBD1, also referred to as California Standard, is one of the first versions of an On-board diagnostic system in any vehicle. It is manufacturer-specific, meaning that every car brand has its own particular scanner that isn’t interchangeable with other brands. The driver will receive the system’s warning via the “check engine” light or MIL (Malfunction Indicator Light). OBD1 codes are a list of trouble codes associated with the on-board diagnostic standard (OBD1) implemented in vehicles made for California from 1991 up to 1995 to control the region’s emissions. People can use an OBD1 scanner to read and clear the fault codes. It will connect to the system to identify the problem, show OBD1 diagnostic codes (DTC, for short), and pinpointing the problem on its screen.

The Difference Between Each Brand And Model

OBD1 is also not standardized, meaning that the location, connector, or the trouble code in each brand will differ from others with the same problem. This article will take General Motor (GM) and Ford to make comparisons:

The Difference In Location Of OBD1 Connectors

The diagnostic connectors that allow communication between the OBD system and the OBD1 scan tool are also located in different locations.

For example, for General Motors (GM) vehicles made before 1995, the connector is located under the driver’s side’s dash panel. It may be covered by a black plastic cover, so you should pay attention to look under it.  For Ford vehicles, the connector is located in the engine compartment by the fender near the battery.

The Difference In The Design Of The OBD1 Connectors

The connectors look different too, below are images of both for easier identification and differentiation. The one used by General Motors has 12 pins. Even though the design varies from manufacturer to manufacturer, the standard pins like the power, ground, and diagnostic pin may be the same in most car brands.

The OBD1 connector may vary depend on the car brandsCre: https://www.youtube.com/watch?v=YIOF08GPAAY
1989 Ford Bronco connector
The OBD1 connector of General Motors has 12 pinsCre: http://tech.oldsgmail.com/ecm_aldl.php
ALDL connector for General Motor vehicle

The Difference In The OBD1 Codes

While diagnosing the car problems, you can notice several OBD1 codes as flashes on the Check Engine Light. As a result of unstandardized, not only the location and connector but also the OBD1 code lists will be different in each car brand, or even the models. It may be the same number, but the meaning or the fault location will vary depending on the brands or models. For examples, when it comes to Ford, we have two test modes, namely:

  1. Key On Engine Off (KOEO)
  2. Key On Engine Running (KOER)

OBD1 Code Lists

As this article has mentioned before, OBD1 is not standardized so the trouble code will vary between all brands. Maybe the same problem but it will have different code meanings or numbers. Here are some lists of OBD1 codes from different brands that may be useful for you.

GM OBD1 Diagnostic Code

CodesMeaning/Fault Location
12No distributor reference pulse (diagnostic test active)
13Oxygen sensor circuit open or no activity
Left bank O2 sensor circuit open or no activity
14Engine coolant temp sensor error (high temp indicated)
15Engine coolant temp sensor error (low temp indicated)
16System voltage too low
17Camshaft position sensor error
21Throttle Position sensor error (signal high)
22Throttle position sensor error (signal low)
23Intake air temp sensor error (low temp indicated)
24Vehicle speed sensor error (open circuit or no activity)
25Intake air temp sensor error (high temp indicated)
26Quad Driver Module (QDM A) error
28 Auto transmission range pressure switch error
31Waste gate solenoid circuit error
Gear Position Switch (PRNDL) error
32EGR system failure
33MAP sensor circuit error (signal high indicating low vacuum)
34MAP sensor circuit error (signal low indicating high vacuum)
35IAC problem or idle error
36MAF sensor error
24x Crankshaft position sensor circuit error
4T60-E Shifting Error
37TCC brake switch circuit error
38TCC brake switch circuit error
39Clutch switch circuit error
TCC error
41Ignition control error
MEM-CAL error
Computer Controlled Ignition Cam Sensor Signal error
42Ignition bypass circuit error
43Knock sensor error
44Oxygen sensor error (lean condition indicated)
Left bank O2 sensor error (lean condition indicated)
45Oxygen sensor error (rich condition indicated)
Left bank O2 sensor error (rich condition indicated)
46Pass-Key II (VATS) system error - circuit out of freq range
47UART (serial data) circuit error
51PROM error
Incorrect MEM-CAL
52Fuel cal-pak incorrect or missing
53System voltage too high
Digital EGR Valve solenoid 1 error
54Fuel pump circuit low voltage
Digital EGR Valve solenoid 2 error
55ECM error
Digital EGR Valve solenoid 3 error
56Quad Driver Module (QDM B) error
57Boost Control error
58Trans fluid temp sensor circuit error (low voltage)
VATS system error
59Trans fluid temp sensor circuit error (high voltage)
61A/C system performance
63Right bank O2 sensor circuit error
MAP sensor circuit signal voltage high (low vacuum indicated)
64Right bank O2 sensor lean exhaust indicated
MAP sensor circuit signal voltage low (high vacuum indicated)
65Right bank O2 sensor rich exhaust indicated
66A/C pressure sensor circuit error (low pressure indicated)
67A/C pressure sensor circuit error
68A/C clutch relay circuit error (shorted to ground)
69A/C clutch relay circuit error (open circuit indicated)
A/C high pressure switch error
70A/C pressure sensor circuit error (high pressure indicated)
71A/C evaporator temp sensor circuit error (low temp indicated)
72VSS signal circuit error
73A/C evaporator temp sensor circuit error (high temp indicated)
75Digital EGR solenoid #1 circuit error
76Digital EGR solenoid #2 circuit error
77Digital EGR solenoid #3 circuit error
79Transmission fluid overtemp
80Transmission component slipping
823x Crankshaft position sensor circuit error
85PROM error
86A/D error
87EEPROM error (flash memory error)
90TCC error
93Transmission pressure control solenoid circuit error
96Transmission system voltage low
98Invalid PCM program
99Invalid PCM program

Ford OBD1 Diagnostic Code

Code Meaning/Fault location
R = Engine running test

M = Memory code

O = Key on - Engine off test
11System OK
12Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) – ISC
13(O)ISC did not respond properly (extends to touch throttle then retracts for KOEO) – ISC
(R)Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too high)
(M)ISC sticking, open ITS circuit or TP sticking
14Ignition pickup (PIP) was erratic – Ignition Systems
E4OD Transmission diesel RPM sensor – Diesel RPM sensor
15(O)No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test Failure)
(M)KAM (pin 1) was interrupted (was battery disconnected?)
161 9L & 2 5L – Throttle stop set too high – IDLE or Idle Set Procedures
2 3L – RPM’s too low – IDLE
(O)Electronic ignition – IDM circuit fault – Ignition Systems
171 9L & 2 5L – Throttle stop set too low – IDLE
18(R)Check base timing & advance function – Timing Tests
(M)Ignition TACH signal erratic – Ignition Systems
Spark Angle Word (SAW) circuit failure (1 9L SFI)
19(O)No Vehicle Power (pins 37 + 57) or bad PCM VPWR Diagnosis
(R)Erratic idle during test (reset throttle & retest) – Idle Set Procedures
Electronic ignition Cylinder ID sensor/circuit problem – Ignition Systems
21Engine Coolant Temperature (ECT) sensor out of range – ECT
22MAP (vacuum) or BARO signal out of range – MAP
23Throttle sensor out of range or throttle set too high – TPS
24Intake Air Temperature (IAT) or Vane Air Temperature (VAT) sensor out of range – IAT VAT
25Knock sensor not tested (ignore if not pinging) – KS
26Mass Air Flow (MAF) or Vane Air Flow (VAF) out of range – MAF VAF
Transmission Oil Temperature (TOT) sensor out of range, Transmissions
27Vehicle Speed Sensor problem – VSS
28Vane Air Temperature (VAT) sensor out of range – VAT
2 3L w/Electronic Ignition – Cyl ID, IDM low or right coil pack failure – Ignition Systems
29Vehicle Speed Sensor problem – VSS
31(O,R,M)EVP – EVP signal is/was out of range – EVP
EVR – EVP signal is/was low – EVR
PFE – PFE signal is/was low – PFE
32(R)EVP – EGR not responding properly during test – EVP
(O,R,M)EVR – EVP signal is/was low – EVR
(R,M)PFE – PFE shows low pressure, EGR not seating or memory, not seating intermittently – PFE
37(O,M)ALL – EGR did not open/ respond during test or if memory code, did not open intermittently – EVP EVR PFE
34(R)EVP – EGR did not respond properly during test – EVP
(O,R,M)EVR – EVP sensor is/was high – EVR
PFE – PFE sensor is/was out of range – PFE
35(R)EVP – Engine RPM’s too low to test EGR system – EVP
(O,R,M)EVR – EVP sensor signal is/was high – EVR
PFE – PFE sensor signal is/was high – PFE
38Idle Tracking Switch signal was intermittent – ISC
39 Transmission Torque Converter clutch not engaging – Transmissions
41  (R)System lean – Fuel control
(M)System was lean for 15 seconds or more (no HO2S switching) – Fuel control
42  (R)System rich – Fuel control
(M)System was rich for 15 seconds or more (no HO2S switching) – Fuel control
43 (R)HO2S sensor not reading (run at 2000 rpm’s for 2 minutes and retest – check  for HO2S switching)
(M)Was lean at WOT for 3 seconds or more – Fuel control
44 AIR system inoperative – Air Injection
45 AIR not Diverting (AIRD) – Air Injection
Electronic Ignition – coil primary circuit failure – Ignition Systems
46AIR Bypass (AIRB) not working – Air Injection
Electronic Ignition – primary circuit failure coil 2 – Ignition Systems
47 Low flow unmetered air (check for small vacuum leaks, injector o’rings, gaskets etc )
E4OD transmission 4×4 switch/circuit problem – Transmissions
48 High flow unmetered air (check for large vacuum leak, inlet hoses etc )
Electronic Ignition – coil primary circuit failure – Ignition Systems
49Electronic Ignition – spout signal circuit problem – Ignition Systems
Transmission 1/2 shift problem – Transmissions
51Engine Coolant Temperature (ECT) sensor signal is/was too high – ECT
52 Power Steering Pressure Switch/circuit open – PSP
  (R)Did you turn wheel during test ?
53 Throttle Position sensor too high – TPS
54Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal high – IAT VAT
55 No or low (under 7 5 V) Key Power to PCM pin 5
56 Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high – VAF MAF
Transmission Oil Temperature sensor too high – Transmissions
57Intermittent in Park/Neutral/ Switch or Neutral Pressure switch circuit – PNP or Transmissions
58Idle Tracking Switch (ITS) signal problem ISC
Vane Air Temperature (VAT) sensor out of range or open – VAT
59 AXOD 4/3 circuit fault – Transmissions
3 0L SHO – Low speed fuel pump circuit problem – Power / Fuel Pump Circuits
Transmission 2/3 shift problem – Transmissions
61Engine Coolant Temperature (ECT) sensor is or was too low – ECT
62AXOD (KOEO only) 3/2 circuit short to ground – Transmissions
AXOD (KOEO AND KOER) 4/3 circuit failure – Transmissions
E4OD excessive converter clutch slippage – Transmissions
63Throttle Position Sensor (TPS) signal too low TPS
64Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal low or grounded – IAT VAT
65 Check intermittent HO2S (signal or ground) – Fuel Control
   (R)E4OD truck – cycle OD cancel switch after engine ID is received – Transmissions
1984 3 8L ONLY – O, M Battery voltage high (check for electrical system overcharging)
66Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low – VAF MAF
Transmission Oil Temperature (TOT) signal low (possibly grounded) – Transmissions
67 Park/Neutral circuit fault – PNP
Transmission Manual Lever Position (MLP) sensor circuit – Transmissions
(M)Intermittent Park Neutral Position (PNP) sensor fault – PNP
68Idle Tracking Switch (ITS) circuit (possibly grounded) – ISC
Vane Air Temperature (VAT) sensor out of range or grounded – VAT
3 8L AXOD -Transmission Temperature Switch (TTS) open – Transmissions
Electronic Transmission – Transmission Oil Temperature (TOT) sensor was overheated -Transmissions
69 AXOD transmission (O) 3/2 switch closed (possible short circuit) – Transmissions
AXOD (M) 3/2 switch open (poss short to power) – Transmissions
E4OD 3/4 shift problem – Transmissions
70    (M)3 8L AXOD – Data link to instrument cluster fault Service any other EEC codes, erase memory and retest   If code is still present refer to instrument cluster diagnosis manual
71     (M)1 9L TBI, 2 3L TBI, 2 5L TBI – ITS signal was grounded when throttle should have been opening  ITS-ISC ISC motor problem or Idle Tracking Switch (ITS) signal wire shorted to  ground – ISC
  (M)1 9L MFI – PCM re-initialized  Possible electrical noise, case ground or intermittent  VPWR problem – VPWR Diagnosis
  (M)3 8L AXOD – Data link to instrument cluster fault – See code 70
72   (R)No MAP or MAF change in “goose” test – retest, check for frequency or   voltage change – MAP MAF
(M)1 9L MFI – VPWR circuit to PCM was intermittent – VPWR Diagnosis
(M)2 3L T/C – PCM re-initialized  Possible electrical noise, case ground or  intermittent VPWR problem – VPWR Diagnosis
(M)3 8L AXOD – Message center data link circuit fault – See code 70
73  (O)Rerun test, if 73 is still output replace TPS
(R)No Throttle Position Sensor (TPS) change in “goose” test  Must get at least 25% throttle rotation – TPS
74Was brake depressed after engine ID was received ?
Brake On Off (BOO) signal open or short to ground – BOO
75Brake On Off (BOO) signal shorted to power – BOO
76Vane Air Flow (VAF) did not respond to “goose” test – VAF
77System did not receive “goose” test – see TESTS
78   (M)VPWR circuit to PCM was intermittent or the PCM is bad VPWR Diagnosis
79 A/C is on or pin 10 is shorted to power
81Boost control solenoid – Solenoids
AIRD solenoid – Solenoids and Air Injection
3 0L SHO – Inlet Air Solenoid – Solenoids
822 3L TC – Fan Control wire shorted to ground – A/C and Fan Circuits
AIRB solenoid – Solenoids and Air Injection
3 8L SC – Super Charger Bypass Solenoid – Solenoids
83High Electro Drive Fan circuit fault – A/C and Fan Circuits
EGR Control solenoid – Solenoids
3 0L SHO – Low Speed Fuel Pump Relay circuit – Power / Fuel Pump Circuits
84EGR Vacuum Regulator – Solenoids
EGR cutoff solenoid – Solenoids
EGR Vent solenoid – Solenoids
852 3L T/C Automatic – 3/4-4/3 Shift solenoid – Transmissions
CANP solenoid (ALL 1989) – Solenoids
(M)1 9L MFI – System has corrected rich condition – Fuel control
86 2 3L or 2 9L Truck – A4LD 3/4 shift solenoid – Transmissions
(M) 1 9L MFI – System has corrected lean condition – Fuel control
87(O)Fuel pump circuit fault (check inertia switch) – Power / Fuel Pump Circuits
Vehicles with 2BBL carb – Temperature Compensated Accelerator Pump  Solenoid – Solenoids (M) intermittent in fuel pump primary circuit – Power / Fuel  Pump Circuits NOTE: On some Escorts with automatic seat belts this code is normal IN MEMORY due to the wiring
88Throttle Kicker Solenoid – Solenoids
Variable Voltage Choke relay circuit fault – VVC
Fan Control circuit fault – A/C and Fan Circuits
A4LD – Converter Clutch Override solenoid – Transmissions
Electronic Ignition – IDM, DPI or spout circuit fault – Ignition Systems
89A4LD – Converter Clutch Override solenoid – Transmissions
AXOD Torque Converter Control solenoid circuit – Transmissions
Exhaust Heat Control (heat riser) solenoid circuit – Solenoids
91(R, M)System running lean – Fuel control
Transmission SS 1 circuit/solenoid problem – Transmissions
92(R)System running rich – Fuel control
Transmission SS 2 circuit/solenoid problem – Transmissions
93(O,R)Throttle linkage binding or bad ISC motor ISC HO2S not reading Fuel control
Transmission TCC circuit/solenoid problem – Transmissions
94AIR system inoperative – Air Injection
Transmission TCC circuit/solenoid problem – Transmissions
95(O)Fuel pump: open, bad ground or always on – Power / Fuel Pump Circuits
(R)AIR not Diverting (AIRD) – Air Injection
  (M)Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM  (Fuel Pump Monitor signal) – Power / Fuel Pump Circuits
96(O)Fuel pump monitor circuit shows no power – Power / Fuel Pump Circuits
(R)AIR Bypass (AIRB) not working – Air Injection
(M)(Service 87 code first if present) Fuel pump relay or battery power feed was open – Power / Fuel Pump Circuits
97E4OD OD cancel light circuit failure – Transmissions
98(R)Did not pass KOEO yet (Get 11 in KOEO first)
Transmission EPC circuit/solenoid failure – Transmissions
99(R)ISC needs to learn (Let idle for 2 minutes, Erase memory and retest)
Transmission EPC circuit/solenoid failure – Transmissions
111System checks OK
112(O,M)Intake Air Temperature (IAT) sensor is/was low or grounded – IAT
113(O,M)IAT sensor is/was high or open – IAT
114(O,R)IAT sensor out of range – IAT
116(O,R)Engine Coolant (ECT) sensor out of range – ECT
117(O,M)ECT sensor is/was low or grounded – ECT
118(O,M)ECT sensor is/was high or open – ECT
121(O,R,M)Throttle Position (TP) sensor out of range – TPS
122(O,M)TP low (possibly grounded or open circuit) – TPS
123(O,M)TP is/was high or short to power – TPS
124(M)TP voltage was higher than expected – Fuel control
125(M)TP voltage was lower than expected – Fuel control
126(O,R,M)MAP or BARO sensor out of range – “>MAP
128(M)MAP vacuum has not been changing – check vacuum lines – “>MAP
129(R)No MAP or Mass Air Flow sensor change during “goose” test – MAP MAF
136(R)Oxygen sensor not switching/system lean Left or Front HO2S – Fuel control
137(R)Oxygen sensor not switching/system rich Left or Front HO2S – Fuel control
138(R)Fault in Cold Start Injector circuit – Fuel control
139(M)Oxygen sensor not switching Left or Front HO2S – Fuel control
144(M)Oxygen sensor not switching Single, Right or Rear HO2S – Fuel control
157(R,M)Mass Air Flow signal is/was low or grounded – MAF
158(O,R,M)MAF sensor is/was high or short to power – MAF
159(O,R)MAF sensor is/was out of range – MAF
167(R)No Throttle Position sensor change in “goose” test (must get at least 25% rotation) – TPS
171(M)Oxygen sensor not switching – system was at adaptive limits – Single, Right or Rear HO2S – Fuel control
172(R,M)Oxygen sensor not switching – system is or was lean – Single, Right or Rear HO2S – Fuel control
173(R,M)Oxygen sensor not switching – system is or was rich – Single, Right or Rear HO2S – Fuel control
174(M)Oxygen sensor was slow in switching Single, Right or Rear HO2S – Fuel control
175(M)Oxygen sensor not switching – system was at adaptive limits – Left or Front HO2S – Fuel control
176(M)Oxygen sensor not switching – system is or was lean Left or Front HO2S – Fuel control
177(M)Oxygen sensor not switching – system was rich Left or Front HO2S – Fuel control
178(M)Oxygen sensor was slow in switching Left or Front HO2S – Fuel control
179(M)Fuel system was rich at part throttle Single, Right or Rear HO2S – Fuel control
181(M)Fuel system was lean at part throttle Single, Right or Rear HO2S – Fuel control
182(M)Fuel system was rich at idle Single, Right or Rear HO2S – Fuel control
183(M)Fuel system was lean at idle Single, Right or Rear HO2S – Fuel control
184(M)Mass Air (MAF) output higher than expected – Fuel control
185(M)Mass Air (MAF) output lower than expected – Fuel control
186(M)Injector pulse width longer than expected or Mass Air Flow (MAF) lower than expected – Fuel control
187Injector pulse width shorter than expected or Mass Air Flow (MAF) higher than  expected – Fuel control
188(M)Fuel system was rich at part throttle – Left or Front HO2S – Fuel control
189(M)Fuel system was lean at part throttle – Left or Front HO2S – Fuel control
191(M)Fuel system was rich at idle – Left or Front HO2S – Fuel control
192(M)Fuel system was lean at idle – Left or Front HO2S – Fuel control
193Failure in Flexible Fuel (FF) sensor circuit – Fuel control
194(M)Perform cylinder balance test to check for inoperative injectors
195(M)Perform cylinder balance test to check for inoperative injectors
211(M)Ignition PIP signal was erratic or missing – Ignition Systems
212(M)Ignition TACH signal was erratic (module/wiring) or SPOUT circuit fault – Ignition Systems
213(R)Ignition SPOUT or SAW circuit open or shorted – Ignition Systems
214(M)Error in Cylinder ID (CID) circuit or signal – Ignition Systems
215(M)Primary circuit failure – ignition coil 1 – Ignition Systems
216(M)Primary circuit failure – ignition coil 2 – Ignition Systems
217(M)Primary circuit failure – ignition coil 3 – Ignition Systems
218(M)IDM signal open or high or left coil pack failure – Ignition Systems
219(M)SPOUT circuit failure, timing defaulted to 10 degrees – follow code 213 diagnosis
222(M)IDM open or high or right coil pack failure – Ignition Systems
223(M)Dual Plug (DPI), SPOUT or IDM circuit fault – Ignition Systems
224(M)Failure in ignition coil primary circuit – Ignition Systems
225(R)Knock sensor not tested (ignore if not pinging) – KS
226(O)Ignition Diagnostic Monitor (IDM) signal fault – Ignition Systems
232(M)EI primary coil circuit failure – Ignition Systems
238(M)EI primary circuit failure – ignition coil 4 – Ignition Systems
311(R)AIR system not working – Single, Right or Rear HO2S – Air Injection
312(R)AIR not diverting – Air Injection
313(R)AIR not bypassing – Air Injection
314(R)AIR inoperative, Left or Front HO2S – Air Injection
326(R,M)Pressure Feedback EGR shows low pressure EGR not seating or not seating intermittantly – PFE
327(O,R,M)EGR feedback signal is/was low – EVR or PFE
328(O,R,M)EGR Valve Position (EVP) is/was low – EVR
332(R,M)EGR did not open/respond during test or if memory code, did not open intermittantly – EVR or PFE
334(O,R,M)EVP sensor is/was high – EVR
335(O)EGR feedback signal is/was out of range – EVR or PFE
336(O,R,M)PFE sensor signal is/was was high – “>PFE
337(O,R,M)EGR feedback signal is/was was high – EVR
338(M)Cooling system did not heat up (check cooling system / thermostat operation)
339(M)Cooling system overheated (check cooling system / thermostat operation)
341(O)Octane jumper installed (information only code to notify you if it is installed)
411(R)Idle speed system not controlling idle properly (generally idle too high) – ISC
412(R)Idle speed system not controlling idle properly (generally idle too low) – ISC
452(M)Vehicle Speed Sensor (VSS) problem
511(O)No power to PCM pin 1 or bad PCM (processor)
512(M)Memory power (PCM pin 1) was interrupted – Was battery disconnected ?
513(O)Replace processor (PCM) (internal failure)
519(O)PSP switch/circuit open – PSP h Pedal Position (CPP) circuit fault – PNP
528(M)System shows voltage at pin 10 (is A/C on ?) or pin 30 (PNP, CPP switch) – PNP
529(M)Data Communications Link to processor failure Service any EEC codes, erase memory and retest  If code is still present refer to instrument cluster diagnosis manual
533(M)Data Communications Link to instrument cluster failure – see 529
536(O,R,M)Brake On Off open or shorted to ground – BOO
538(R)System did not receive “goose” test – TESTS
539(O)System shows voltage at PCM pin 10  Is A/C on ?
542(O,M)Fuel pump open, bad ground or always on – – Power / Fuel Pump Circuits
543(O)Fuel pump monitor circuit shows no power – Power / Fuel Pump Circuits
(M)(Service 556 code first if present) Fuel pump relay or battery power feed was open – Power / Fuel Pump Circuits
551Problem in Intake Manifold Runner Control (IMRC) solenoid/circuit – Solenoids
552(O)AIRB solenoid/circuit failure – Solenoids
553(O)AIRD solenoid/circuit failure – Solenoids
554(O)Fuel Press Regulator Control solenoid/circuit fault – Power / Fuel Pump Circuits
556(O,M)Fuel pump relay primary circuit fault – Power / Fuel Pump Circuits
557(O,M)Low speed pump relay primary circuit fault – Power / Fuel Pump Circuits
558(O)EGR vacuum regulator solenoid/circuit failure – EVR or PFE or Solenoids
559(O)A/C relay primary circuit fault – A/C and Fan Circuits
563(O)High Fan Control (HFC) circuit failure – A/C and Fan Circuits
564(O)Fan Control (FC) circuit failure – A/C and Fan Circuits
565(O)Canister Purge 1 solenoid/circuit failure – Solenoids
566(O)transmission 3/4 shift solenoid/circuit – Transmissions
569(O)Canister Purge 2 solenoid/circuit failure – Solenoids
578(M)A/C pressure sensor VREF short to ground – A/C and Fan Circuits
579(M)ACP sensor did not change with A/C on – A/C and Fan Circuits
581(M)Cooling fan current was excessive – A/C and Fan Circuits
582(O)Open cooling fan circuit – A/C and Fan Circuits
583(M)Fuel pump current was excessive – Power / Fuel Pump Circuits
584(M)Open power ground circuit – Power / Fuel Pump Circuits
585(M)A/C clutch current was excessive – A/C and Fan Circuits
586(M)Open circuit in A/C clutch – A/C and Fan Circuits
587(O, M)Communication problem between PCM and Variable Control Relay Module (VCRM) – Power / Fuel Pump Circuits
617(M)Transmission shift failure (1/2 shift) – Transmissions
618(M)Transmission shift failure (2/3 shift) – Transmissions
619(M)Transmission shift failure (3/4 shift) – Transmissions
621(O)Solenoid/circuit failure – shift solenoid 1 – Transmissions
622(O)Solenoid/circuit failure – shift solenoid 2 – Transmissions
624(O,M)Solenoid/circuit failure -Electronic Pressure Control (EPC) current is high – Transmissions
625(O,M)Solenoid/circuit failure – Electronic Pressure Control (EPC) current is low – Transmissions
626(O)Transmission Coast Clutch (CCS) Solenoid/circuit fault – Transmissions
627(O)Torque Converter Clutch circuit fault – Transmissions
628(M)Excessive converter clutch slippage – Transmissions
629(O,M)Torque Converter Clutch circuit fault – Transmissions
631(O)Overdrive Cancel Light circuit problem – Transmissions
632(R)E4OD – Transmission Control Switch (TCS) should be cycled once between engine ID and  Goose test
633(O)4x4L switch should be in 4×2 or 4×4 high for the test
634(O,M)Park/Neutral Position (PNP) or Clutch Pedal Position (CPP) circuit fault  Electronic shift transmission – Manual Lever Position (MLP) sensor out of range in Park-Transmissions
636(O,R)Transmission Oil Temperature (TOT) sensor out of range – Transmissions
637(O,M)TOT sensor is/was high or open – Transmissions
638(O,M)TOT sensor is/was low or grounded – Transmissions
639(R,M)Transmission Speed sensor (TSS) circuit fault – Transmissions
641(O)Transmission solenoid/circuit failure Shift Solenoid 3 – Transmissions
643(O,M)Torque Converter Clutch (TCC) circuit – Transmissions
645(M)Transmission 1st gear failure – Transmissions
646(M)Transmission 2nd gear failure – Transmissions
647(M)Transmission 3rd gear failure – Transmissions
648(M)Transmission 4th gear failure – Transmissions
649(M)Transmission EPC system failure – Transmissions
651(M)Transmission EPC solenoid/circuit fault – Transmissions
652(O)Torque Converter Clutch (TCC) circuit fault – Transmissions
654(O)Transmission selector not in PARK – Transmissions
656(M)Torque Converter Clutch (TCC) slip – Transmissions
657(M)Transmission temperature was excessive – Transmissions

Acura & Honda OBD1 Diagnostic Code

CodeMeaning/Fault location
0Electronic control module (ECM)
1Heated oxygen sensor A
2Oxygen content B
3Manifold absolute pressure
4Crank position sensor
5Manifold absolute pressure
6Engine coolant temperature
7Throttle position sensor
8Top dead center sensor
9No.1 cylinder position sensor
10Intake air temperature sensor
11Electronic control module (ECM)
12Exhaust recirculation system
13Barometric pressure sensor
14Idle air control valve or bad ECM
15Ignition output signal
16Fuel Injector
17Vehicle speed sensor
19A/T lock-up control solenoid
20Electric load detector
21V-TEC control solenoid
22V-TEC pressure solenoid
23Knock sensor
30A/T FI signal A
30A/T FI signal B
41Heated oxygen sensor heater
43Fuel supply system
45Fuel supply metering
48Heated oxygen sensor
61Front heated oxygen sensor
63Rear heated oxygen sensor
65Rear heated oxygen sensor heater
67Catalytic converter system
70Automatic transaxle
71Misfire detected cylinder 1
72Misfire detected cylinder 2
73Misfire detected cylinder 3
74Misfire detected cylinder 4
75Misfire detected cylinder 5
76Misfire detected cylinder 6
80Exhaust recirculation system
86Coolant temperature
92Evaporative emission control system

BMW OBD1 Diagnostic Code

CodeMeaning/Fault location
1000End of fault code blinkingness
1444No codes stored
1211DME control module/unit
1215Mass air flow sensor
1216Throttle potentiometer
1218Output stage, group #1, DME 3.3.1 only
1219Output stage, group #2, DME 3.3.1 only
1221Oxygen (EGO) sensor #1
1212Oxygen (EGO) sensor #2
1222Lambda Control 1 or Oxygen sensor lean/rich control stop
1213Lambda Control 2
1223Coolant temperature sensor
1224Air temperature sensor
1225Knock sensor #1, DME 3.3.1 only
1226Knock sensor #2, DME 3.3.1 only
1227Knock sensor #3
1228Knock sensor #4
1231Battery Voltage/DME Main Relay
1232Throttle Idle Switch
1233Throttle WOT Switch
1234Speedometer A signal, DME 3.3.1 only
1237A/C compressor cutoff DME 3.3.1 only
1242A/C compressor signal DME 3.3.1 only
1243Crankshaft Pulse Sensor
1244Camshaft Sensor
1245Intervention AEGS
1247Ignition Secondary Monitor
1251Fuel Injector 1 (or group 1)
1252Fuel Injector 2 (or group 2)
1253Fuel Injector 3
1254Fuel Injector 4
1255Fuel Injector 5
1256Fuel Injector 6
1257Fuel Injector 7
1258Fuel Injector 8
1261Fuel Pump Relay Control
1262Idle Speed Actuator
1263Purge Valve
1264EGO Heater
1265Fault Lamp (check engine)
1266VANOS
1267Air Pump Relay Control
1271Ignition Coil 1
1272Ignition Coil 2
1273Ignition Coil 3
1274Ignition Coil 4
1275Ignition Coil 5
1276Ignition Coil 6
1277Ignition Coil 7
1278Ignition Coil 8
1281DME Control Unit Memory Supply
1282Fault code memory
1283Fuel injector output stage
1286Knock control test pulse

Audi OBD1 Diagnostic Code

CodeMeaning/Fault location
0000End of fault sequence
1111Bad ground to Electronic Control Unit (ECU) or ECU failure-check grounds or replace ECU
1119Transmission Range - Defective wiring. Check for break or short
1213Vehicle Speed Sensor (VSS) - Check transmission speed sender wiring and the wiring of the instrument cluster
1231Vehicle Speed Sensor (VSS) (G54) - Check transmission speed sender wiring and the wiring of the instrument cluster
1232Throttle Position Actuator - Check defective actuator or wiring for break or short.
2111Engine speed sender. (RPM)
2112Ignition reference sender
2113Hall sender - No speed signal from distributor; check Hall sensor and circuits or the air-flow sensor plate is not moving freely; adjust potentiometer or lever.
2114Hall sender not on reference point or distributor out of position.
2121Idle switch - check switch & circuit.
2122Hall sender - Check wiring for break or short.
2123Full throttle switch; check switch & circuit.
2132Electronic Control Module (ECM) - No ignition to injection signal.
2141Knock sensor 1 control at maximum retard - test compression, change octane, adjust timing, check knock-sensor wires.
2142Knock sensor 1 signal - Test sensor, check wiring for break or short.
2143Knock sensor 2 control at maximum retard - test compression, change octane, adjust timing, check knock-sensor wires.
2144Knock sensor 2 signal; test sensor.
2212Throttle Potentiometer - Value out of range.
2214RPM Signal - Idle speed to high or engine over-revved
2221Vacuum Control - No vacuum to control unit. Check for leaks.
2222Manifold Vacuum - Check vacuum line and waste gate for leaks. Pressure sensor - Sensor defective
2223Altitude Sensor - Check sensor, check wiring for break or short.
2224Turbo/Manifold pressure - Check turbo control wiring, check for over boost, air leak, defective waste gate valve, vacuum leak or defective pressure sensor.
2231Idle-speed stabilizer adjustment limits exceeded; too-fast idle. Adjust throttle for full closing, check for vacuum leak, check ignition timing. Or air Mass Sensor - Check sensor and wiring.
2232Air mass/flow sensor - No signal. Check wiring for break or short.
2233Air mass/flow sensor reference voltage open or short circuit
2234ECM Supply voltage low.
2242CO-potentiometer voltage low
2312Coolant temperature sensor - Check wiring, check resistance.
2314Transmission to Engine control module circuit. - Check wires for breaks or shorts.
2322Intake Air Temperature Sensor - Check sensor and wiring.
2323Mass Airflow Sensor - Check sensor and wiring for breaks.
2324Mass Airflow Sensor - Check sensor and wiring for breaks or shorts to B+ or ground or check for air leak.
2331Oxygen Sensor Control - Out of range. - Check ignition, air intake for leaks and injectors.
2332Oxygen Sensor - Bank 2 - Check wiring for breaks or shorts.
2341Oxygen sensor (O2) at control limit; check CO, lambda-sensor wire, lambda-sensor control, start valve, evaporative system and check for vacuum leaks.
2342Oxygen Sensor Control - no signal - Check wiring, sensor.
2343Rich limit; the pressure regulator has exceeded +10 mA for more than 5 minutes, closed-loop; check for vacuum leaks.
2344Lean limit; the pressure actuator has exceeded -5mA for more than 5 minutes, closed loop; check idle.
2411EGR System Malfunction
2412Intake Air Temperature Sensor - Check sensor and wiring for breaks or shorts
2413Mixture Control - Running rich
Fuel pressure too low
3424Malfunction Indicator Lamp (MIL) failure - Check lamp and wiring.
4311Secondary Air Injection Pump Relay - Check relay and wiring.
4312EGR Frequency Valve
4313Secondary Air Injection Solenoid Valve - Check valve and wiring.
4331EVAP Carbon Canister Solenoid Purge Valve 2
4332Ignition Circuit Final Stage - Check for breaks or short to ground or B+ or bad ECM.
4343EVAP Carbon Canister Solenoid Purge Valve 1
4411Fuel Injector Cylinder 1 or 1 & 5
4412Fuel Injector Cylinder 2 or 2 & 7
4413Fuel Injector Cylinder 3 or 3 & 6
4414Fuel Injector Cylinder 4 or 4 & 8
4421Fuel Injector Cylinder 5
4422Fuel Injector Cylinder 6
4423Fuel Injector Cylinder 7
4424Fuel Injector Cylinder 8
4431Idle Air Control Valve / Idle Stabilizer - Check valve and wiring.
4433Fuel Pump Relay
4442Waste gate - Defective frequency valve or wiring.
Boost pressure circuit - Check for short.
4443EVAP Canister purge valve.
4444No fault in system.

Nissan OBD1 Diagnostic Code

CodeMeaning/Fault location
11Crank Angle Sensor/Camshaft Position Sensor
12Air Flow Meter/Mass Air Flow Sensor
13Engine Coolant Temperature Sensor
14Vehicle Speed Sensor
21Ignition Signal
22Fuel Pump
23Idle Switch
24Throttle Valve Switch
25Idle Speed Control Valve
28Cooling Fan Circuit
31ECM
32EGR Function
33Heated Oxygen Sensor
34Knock Sensor
35Exhaust Gas Temperature Sensor
36EGR Control-Back Pressure Transducer
37Knock Sensor
38Right hand bank Closed Loop (B2)
41Intake Air Temperature Sensor
42Fuel Temperature Sensor
43Throttle Position Sensor
44ECCS Normal Operation
45Injector Leak
47Crankshaft Position Sensor
51Injector Circuit
53Oxygen Sensor
54A/T Control
55No Malfunction
63No. 6 Cylinder Misfire
64No. 5 Cylinder Misfire
65No. 4 Cylinder Misfire
66No. 3 Cylinder Misfire
67No. 2 Cylinder Misfire
68No. 1 Cylinder Misfire
71Random Misfire
72TWC Function right hand bank
76Fuel Injection System Function right hand bank
77Rear Heated Oxygen Sensor Circuit
82Crankshaft Position Sensor
84A/T Diagnosis Communication Line
85VTC Solenoid Valve Circuit
86Fuel Injection System Function right hand bank
87Canister Control Solenoid Valve Circuit
91Front Heated Oxygen Sensor Heater Circuit right hand bank
94TCC Solenoid Valve
95Crankshaft Position Sensor
98Engine Coolant Temperature Sensor
101Front Heated Oxygen Sensor Heater Circuit right hand bank
103Park/Neutral Position Switch Circuit
105EGR and EGR Canister Control Solenoid Valve Circuit
108Canister Purge Control Valve Circuit

Lexus OBD1 Diagnostic Code

CodeMeaning/Fault location
12RPM Signal
13RPM Signal
14Ignition Signal
15Ignition Signal
16Electronically Controlled Transmission Control Signal
17CMP No. 1
18CMP No. 2
21Main O2S & Heater Signal
22ECT Sensor Signal
24IAT Sensor Signal
25Air–Fuel Ratio Lean Malfunction
26Air–Fuel Ratio Rich Malfunction
27Sub O2S Signal
28Main O2S
29Sub O2S
31Air Flow Meter Signal
32Air Flow Meter Signal
35HAC/Barometric Pressure Sensor Signal
41TP Sensor Signal
42VSS Signal
43Starter Signal
47Sub TP Sensor
48Secondary Injection System Malfunction
51Switch Condition Signal
52KS Signal
53Knock Control Signal
55KS Signal
70EGR System Malfunction
71EGR System Malfunction
78Fuel Pump Control

Subaru OBD1 Diagnostic Code

CodeMeaning/Fault location
11No signal entered from crank angle sensor but signal entered from cam angle sensor
12Too low or too high voltage signal emitted from ignition (starter) switch
13No signal entered from cam angle sensor but signal entered from crank angle sensor
14Fuel injector #1 inoperative (too low or too high voltage signal emitted from monitor circuit)
15Fuel injector #2 inoperative (too low or too high voltage signal emitted from monitor circuit)
16Fuel injector #3 inoperative (too low or too high voltage signal emitted from monitor circuit)
17Fuel injector #4 inoperative (too low or too high voltage signal emitted from monitor circuit)
21Too low or too high voltage from water temperature sensor
22Too low or too high voltage produced in knock sensor monitor circuit
23Too low or too high voltage input entered from air flow sensor
24Air control valve inoperative (too low or too high voltage signal produced in monitor circuit)
26Air temperature sensor fault
31Too low or too high voltage input entered from throttle sensor
32Oxygen sensor inoperative
33Too low or too high voltage input entered from speed sensor
35Solenoid valve inoperative
36Ignition circuit fault
41Faulty learning control function, or adaptive fuel control exceeded limits
42Too low or too high voltage input entered from idle switch
43Throttle switch fault
44Waste gate control solenoid valve inoperative (Turbo only)
45Faulty sensor (BARO)
Faulty sensor or pressure exchange solenoid valve inoperative (Turbo only)
49Use of improper air flow sensor
51Too low or too high voltage signal entered from neutral switch
Too low or too high voltage signal entered from inhibitor switch
52Too low or too high voltage signal entered from parking switch
62Electric load signal fault
63Blower fan switch fault
65Vacuum pressure sensor fault

Mazda OBD1 Diagnostic Code

CodeMeaning/Fault Locations
1Ignition pulse missing
2Diesel: Engine speed (RPM) sensor – no signal
Petrol: Crankshaft position (CKP) sensor/engine speed (RPM) sensor – no signal
3Camshaft position (CMP) sensor – no signal
4Diesel: Crankshaft position (CKP) sensor – no signal
Petrol: Crankshaft position (CKP) sensor/engine speed (RPM) sensor – no signal
5Knock sensor (KS)
6Vehicle speed sensor (VSS)
8Mass air flow (MAF) sensor/volume air flow (VAF) sensor
9Engine coolant temperature (ECT) sensor
10Intake air temperature (IAT) sensor
11Intake air temperature (IAT) sensor
12Throttle position (TP) sensor
14Barometric pressure (BARO) sensor
15Except V6: Oxygen sensor (O2S)/heated oxygen sensor (HO2S) – no activity
V6: Heated oxygen sensor (HO2S), bank 2 – no activity
16Exhaust gas recirculation (EGR) valve position sensor
17Except V6: Oxygen sensor (O2S)/heated oxygen sensor (HO2S) – incorrect signal
V6: Heated oxygen sensor (HO2S), bank 2 – incorrect signal
18Fuel quantity adjuster
19Fuel quantity adjuster position sensor
22Fuel shut-off solenoid
23Diesel: Fuel temperature sensor
Petrol: Heated oxygen sensor (HO2S), bank 1 – no activity
24Heated oxygen sensor (HO2S), bank 1 – incorrect signal
25Fuel pressure regulator control solenoid
26Evaporative emission (EVAP) canister purge valve
28Exhaust gas recirculation (EGR) solenoid – vacuum
29Exhaust gas recirculation (EGR) solenoid – vent
34Idle air control (IAC) valve
35Fuel pressure regulator control solenoid 2
36Glow plug relay
41Intake manifold air control solenoid 1
43Fuel injection timing sensor
46Petrol: Intake manifold air control solenoid 2
Diesel: Closed throttle position (CTP) switch
49Engine control module (ECM) – defective
52Module coding plug
55Input shaft speed (ISS) sensor/turbine shaft speed (TSS) sensor
56323: Engine control module (ECM) – supply voltage
626: Transmission fluid temperature (TFT) sensor
57Engine control relay
60Shift solenoid (SS) A, 1-2
61Shift solenoid (SS) B, 2-3
62Shift solenoid (SS) C, 3-4
63Torque converter clutch (TCC) control solenoid
64Shift timing solenoid, 3-2
65Torque converter clutch (TCC) solenoid
66Transmission fluid pressure (TFP) solenoid
67Engine coolant blower motor relay – low temperature
68Engine coolant blower motor relay – high temperature
69Engine coolant blower motor temperature sensor
71Engine control module (ECM)/immobilizer control module – communication error
72Ignition key – not programmed into ECM
73Engine control module (ECM)/immobilizer control module – immobilizer codes do not match
74Engine control module (ECM)/immobilizer control module – ignition key codes not match
75Engine control module (ECM) – EEPROM error
76Engine control module (ECM) – immobilizer code not stored
77Immobilizer control module – communication error

Toyota OBD1 Diagnostic Code

CodeMeaning/Fault location
1Normal Condition.
2Air Flow Meter signal.
3Ignition signal.
4Engine Coolant Temperature Sensor signal.
5Oxygen Sensor.
6RPM signal (Crank Angle Pulse).
7Throttle Position Sensor signal.
8Intake Air Temperature Sensor signal.
9Vehicle Speed Sensor signal.
10Starter signal.
24Switch signal.
Momentary interruption in power supply to ECU (electronic control unit or computer) up to 1991
12Engine revolution signal missing
13RPM signal to ECU missing above 1000 rpm
14Igniter signal to ECU missing
16A/T control signal missing from ECU
21Main oxygen sensor signal fault
22Water temperature sensor circuit fault
23Intake air temperature signal fault
24Intake air temperature signal fault
25Air/fuel ratio LEAN
26Air/fuel ratio RICH
27Sub-oxygen sensor signal or heater circuit fault
28No. 2 oxygen sensor/heater signal fault
52Too low or too high voltage signal entered from parking switch
31Air flow meter circuit or Vacuum sensor signal fault
32Air flow meter circuit or Vacuum sensor signal fault
34Turbo-charging pressure signal fault
35Altitude compensation sensor signal fault
36Turbo-charging pressure signal fault
41Throttle position circuit fault
42Vehicle speed sensor circuit
43No starter signal to the ECU
51AC signal on; DL contact off (in transmission shifter with diagnostic connector jumped)
52Knock sensor fault Code 71 EGR system malfunction
53Knock sensor fault Code 71 EGR system malfunction
55Knock sensor fault Code 71 EGR system malfunction
72Fuel cut solenoid signal fault
78Fuel pump control signal fault
81TCM communication fault
83TCM communication fault
84TCM communication fault
85TCM communication fault

Jeep OBD1 Diagnostic Code

CodeMeaning/Fault location
11No crank reference signal detected during engine cranking. Intermittent loss of either camshaft or crankshaft position sensor.
12Positive battery input to PCM was disconnected within the last 50 Key-on cycles.
13No difference recognized between the engine MAP reading and the barometric (atmosphere) pressure reading from start-up.
14MAP sensor input above or below acceptable voltage. 5 volt output to MAP sensor open.
15No vehicle speed sensor signal detected during driving load conditions.
17Engine did not reach operating temperature within acceptable limits
21Upstream oxygen sensor response slower than minimum required switching frequency.
Upstream oxygen sensor heating element circuit malfunction.
Downstream oxygen sensor heating element circuit malfunction.
Downstream oxygen sensor input voltage maintained above the normal operating range.
Oxygen sensor voltage too low, tested after cold start. (Upstream or Downstream)
Left oxygen sensor input voltage maintained above the normal operating temperature.
22Engine coolant temperature sensor above or below acceptable voltage.
23Intake air temperature sensor input above or below acceptable voltage.
24Throttle position sensor input above or below acceptable voltage. TPS signal does not correlate to MAP sensor.
25A shorted or open condition detected in one or more of the idle air control motor circuits. Actual idle speed does not equal target idle speed.
27Injector #1 through 6, or any combination of individual injectors driver does not respond properly to the control signal.
31An open or shorted condition detected in the A/C clutch relay circuit. Insufficient or excessive vapor flow detected during fuel evaporation emission system operation.
33An open or shorted condition detected in the duty cycle purge solenoid circuit. (A/C clutch relay circuit)
34An open or shorted condition detected in the Speed Control vacuum or vent solenoid circuits. Speed control switch input below the minimum acceptable voltage.
37Relationship between engine speed and vehicle speed indicates no torque converter clutch engagement.
An open or shorted condition detected in the torque converter part throttle unlocks solenoid control circuit.
Incorrect input state detected for the Park/Neutral switch. Auto only.
41An open or shorted condition in the generator field control circuit.
42An open or shorted condition detected in the auto shutdown relay circuit.
An open condition detected in the ASD relay output circuit
An open or shorted condition detected in the fuel pump relay control circuit
An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit.
No movement of fuel level sender detected.
43Peak primary circuit current not achieved with maximum dwell time
Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cylinders.)
44Battery temperature sensor in voltage above or below acceptable range.
46Battery voltage sense input above target charging voltage during engine operation.
47Battery voltage sense input below target charging during engine operation. Also, no significant change detected in battery voltage during active test of generator output circuit.
51A lean air/fuel mixture has been indicated by an abnormally rich correction factor.
52A rich air/fuel mixture has been indicated by an abnormally rich correction factor.
53PCM Internal fault condition detected.
54No camshaft signal detected during engine cranking.
55Completion of fault code display on Check Engine lamp.
62PCM Failure to update service reminder indicator
63Unsuccessful attempt to write to an EEPROM location by the PCM.
64Catalyst efficiency below required level. (Same as code 72)
65Power steering high pressure seen at high speed. (2.5L only)
72Catalyst efficiency below required level. (Same as code 64)
77Malfunction detected with poser feed to speed control servo solenoids

Dodge OBD1 Diagnostic Code

CodeMeaning/Fault location
11Timing belt skipped 1 tooth or more from initial learned value, Intermittent loss of either camshaft or crankshaft position sensor, No crank reference signal detected during engine cranking
12Direct battery input to PCM was disconnected within the last 50 key-on cycles (normal)
13Engine Coolant Temperature Sensor
14No change in MAP from start to run
15No vehicle speed sensor signal
17Closed loop temp not reached or engine cold too long
21Oxygen sensor problem, upstream or down stream
22Engine coolant temp sensor out of range
23Intake air temp sensor out of range
24Throttle Position sensor out of range
25Idle air control motor circuits, target idle not reached (+/- 200),vacuum leak found
27Injector control circuit
31EVAP purge flow monitor failure or EVAP solenoid circuit
32EGR system failure
33A/C clutch relay circuit
34Speed control Solenoid circuits
35Rad Fan control relay circuit
37Torque converter clutch solenoid CKT or park/neutral switch failure
41Generator field not switching properly
42Fuel pump relay control CKT, Auto shutdown relay control CKT, No ASD relay output voltage at PCM, Fuel level sending unit volts out of range, Fuel level unit No change over miles
43Multiple/ single cylinder misfire
44Battery temp sensor volts out of range
46Charging system voltage too low
51Fuel system lean
52Fuel system rich
53Internal control failure
54No Cam signal at PCM
55End of error messages
62PCM failure SRI mile not stored
63PCM Failure EEPROM write denied
64Catalytic Converter Efficiency Failure
65Power steering switch failure

Chrysler OBD1 Diagnostic Code

CodeMeaning/Fault location
11Camshaft signal or ignition signal, no reference signal during cranking.
12Memory to controller has been cleared within 50-100 engine starts.
13MAP sensor not detecting any change during test.
14MAP voltage too high or too low.
15Vehicle speed sensor, no signal detected.
16Knock sensor circuit. Open or short detected.
17Low engine temperature, possible thermostat fault.
21Oxygen sensor signal, neither rich nor lean detected.
22Coolant sensor voltage low.
23Air charge voltage high/low detected.
24Throttle position sensor voltage high/low.
25Automatic idle speed motor driver circuit, short or open detected.
26Injectors 1 2 and 3 peak current not reached.
27Injector control circuit does not respond to control signal.
31Purge solenoid circuit, open or short detected.
32EGR solenoid circuit, open or short detected.
33A/C clutch relay circuit, open or short detected.
34Speed control servo solenoid, open or short detected.
35Radiator fan control relay circuit, open or short detected.
36Waste-gate solenoid, open or short detected.
37Part throttle unlock (PTU) circuit, open or short detected.
41Charging system circuit not responding to control signal
42Fuel pump or auto shutdown (ASD) relay voltage sensed at controller.
43Ignition control circuit not responding.
44Battery temperature voltage circuit problem.
45Turbo boost limit exceeded-map sensor detects over-boost.
46Battery voltage too high.
47Battery voltage too low.
51Air/fuel at limit.
52Logic module fault.
53Internal controller failure.
54Camshaft reference circuit not detected.
55End of error message.
61BARO read solenoid, open or short detected.
62EMR mileage not stored.
63Eprom write denied.
64Flex fuel sensor signal out of range.
65Manifold tuning valve, open or short detected.
66No CCD messages.
76Ballast bypass relay, open or short detected.
77Speed control relay, open or short detected.

Saturn OBD1 Diagnostic Code

CodeMeaning/Fault location
11Transaxle codes present
12Diagnostic check only
13Oxygen sensor, circuit open or not ready
14Coolant sensor/high temperature
15Coolant sensor/low temperature
17PCM fault – pull-up resistor
196X signal fault (92-95 models)
21Throttle position sensor-voltage high
22Throttle position sensor-voltage low
23IAT circuit low
24VSS circuit-no signal
25IAT circuit-Temp out of high range
26Quad driver output fault
32EGR system fault
33MAP sensor – voltage out of range high
34MAP sensor – voltage out of range low
35IAC – rpm out of range
41Ignition control circuit open or shorted
A EST circuit open
B EST circuit shorted
42EST bypass, open or shorted
A Bypass circuit grounded
B Bypass circuit open
C Bypass circuit shorted
43Knock sensor circuit shorted or open
44Oxygen sensor indicates system lean
45Oxygen sensor indicates system rich
46Power steering pressure switch circuit, open
49Idle rpm out of limit high (vacuum leak)
51PCM memory error
55A/D convertor error in PCM
81ABS message fault (1993+ vehicles with TCS)
82PCM internal communication fault

Final Thoughts

The introduction of the OBD1 system marked one of the greatest advancements in the automobile industry. Even though it was limited in functionality, the system paved the way for a more efficient and useful OBD2 system. OBD1 systems can be troublesome and very frustrating, but their significance is unforgettable. 

This article has dealt with the meaning of OBD1 codes in many brands. You can now understand how they work and how to use them for your benefit. I hope you got all the answers you were looking for.

FAQs

How Can I Check GM OBD1 Codes Without Any Scanner?

Pay attention to the GM OBD1 connector schematic below. It shows the purpose of each slot on the connector. Be careful not to connect the wrong parts. What you will need to do to get the OBD1 codes is to short the circuit between pin A and pin B.

This process will enable the car to enter into a diagnostic mode by flashing the Check Engine Light a couple of times. The goal is to count the flashes, which will give us the OBD1 codes you need.

Follow these simple steps carefully to check the OBD1 codes on your GM car without any scanner:

Step 1: Make sure you have your car battery charger connected to avoid unnecessary error codes and diagnostic issues.

Step 2:  Carefully place a jumper wire between pin B and pin A, making sure not to insert in the wrong pin.

Step 3: After letting the jumper wire stay put, turn the ignition ON, remembering not to start the engine.

Step 4: At this point, you may notice that the Check Engine Light has begun to flash. Start counting the flashes. In the presence of more than one OBD1 code, you will see longer pauses between codes and shorter pauses between the trouble code’s digits. This is to say that if the code is 14, you will notice one flash, a pause, and then four flashes. After all the DTCs are scanned, it will flash code 12, which is one flash, a pause, and then two flashes.

Step 5: Take note of all the OBD1 codes scanned and refer them to the OBD1 diagnostic codes list specific to the GM car you own. You can now remove the jumper wire and battery charger. You have finished checking the codes all on your own.

How Do I Know My Car Is OBD1 Or OBD2?

There are two ways of knowing if your car is OBD1 or OBD2.

The year and place it was manufactured or bought when new

Cars manufactured in the USA in and after 1996 have the OBD2 system. However, depending on the country and the market it was marketed for, your vehicle may have a different system from those of other cars made in the same year.

In Europe, most petrol cars sold new between 2001 and 2004 have an OBD2 system. However, most vans, trucks, and 4*4 vehicles in Europe were not using the OBD2 system till 2007. You can confirm the year your car was manufactured by looking up your model online. Below is a list of countries and years in which the vehicles in those countries became OBD2 compatible.

CountryYear
United States1996
European Union (Diesel)2007
European Union (Petrol)2002
Canada1998
Australia (Diesel)2007
Australia (Petrol)2006
China (Petrol)2008
China (Diesel)2011
China (Petrol)2010
Hong Kong2006
Mexico2007
Morocco2010
New Zealand (Diesel)2007
New Zealand (Petrol)2006
Nigeria2015
Peru2003
Peru2017
Philippines2016
Singapore2014
Taiwan2008
Thailand2013
Turkey2013
United Arab Emirates2018

Check under the hood.

There is a sticker under the hood of every car that will show if your car is OBD2 compliant. It will look similar to the image shown below:

An OBD2 compliant

Can An OBD2 Scanner Read OBD1 Codes?

Unfortunately, it can’t. The OBD2 scanner is only matched with the OBD2 system. Even the adapter cable can’t change anything in the system. However, there are many professional scanners that are so advanced to use for scanning in both OBD1 and OBD2 vehicles, but the price will be expensive.

Leave a Comment

Your email address will not be published. Required fields are marked *