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P1443 Ford: Evaporative Emission Control System Control Valve

P1443 Ford engine code is a common DTC that is easy to fix with the right tools and skill.

The code is largely associated with a faulty purge control valve in the vehicle’s EVAP system.

This article dives into all the symptoms, possible causes, and how to diagnose and fix the issues associated with the p1443 code.

P1443 Ford Code Definition – What Does It Mean?

General Definition

The p1443 OBD 2 code is defined as “Evaporative Emission Control System Control Valve.”

P1443 is a manufacturer-specific diagnostic trouble code (DTC) synonymous with models like Ford, Lincoln, Mercedes, Mercury, and Jaguar.

In some Ford models, the manufacturer uses a qualifier to specifically pinpoint the issue: “Evaporative Emission Control System Control Valve (low/no flow).”

Meaning of P1443

The P1443 is set when the Powertrain Control Module detects a malfunction of the purge control valve in the Evaporative Emission System.

Different brands use different ways to test for evaporative emissions. Ford uses a vacuum-based EVAP system to capture and contain fuel vapors before they leave the system and leak into the atmosphere.

The figure below shows a typical layout for the vacuum-based evaporative emissions system. The system shows an interrelation between the power control module and three other components, namely;

  1. Canister Purge Solenoid (CPS),
  2. Canister Vent Solenoid (CVS)
  3. Fuel Tank Pressor sensor (FTPS)
Cre: https://www.motor.com/magazine-summary/fords-evap-system-operation-testing
Ford’s EVAP system with its associative components | Courtesy of Robert Bosch LLC

Symptoms Of Code P1443 In Ford

  1. Vehicle may exhibit rough idling and high-speed idling.
  2. The vehicle may fail an emissions test.
  3. Additional codes are set on the Powertrain Control Module (PCM).
  4. An illuminated Check Engine Light (CEL) /Service Engine Soon Warning Light.

Causes Of P1443 Ford Code

  1. Faulty or broken purge control valve.
  2. Poor electrical connection in the EVAP purge control valve circuit.
  3. Defective fuel tank pressure sensor.
  4. Burnt, corroded, or disconnected wiring and connectors around the EVAP system.
  5. Blocked hose or connectors between the purge control valve and fuel tank pressure sensor (FTPS).
  6. Faulty or malfunctioning charcoal canister.
  7. Dislodged or damaged vacuum lines.
  8. Faulty or damaged PCM that may need reprogramming or replacement.

How To Diagnose And Fix The Code

Tips

  1. You will need to find a repair manual for this problem. A detailed diagram of your car components will also help you to locate the various parts of the EVAP system.
  2. Tools that will be required for this diagnosis and fix;
    • OBD2 scan tool or an OEM equivalent scanner with control functions.
    • Vacuum pump fitted with a gauge.
    • Test lamp/ voltage tester.
    • Digital multimeter and the battery.
  3. In 90% of cases, the failure of the purge control valve is a result of high temperatures and engine vibrations under the bonnet. An important tip to help prevent this untimely failure is to shield it using a thin aluminum foil shield. You can find these shields in DIY exhaust repair kits available in the market.
OBD2 scanner is a good tool to diagnose P1443
OBD2 scanning tool

Step 1

Use the OBD scan tool to record all the Diagnostic Trouble Codes (DTC) stored in the PCM. This data will enable you to pinpoint all the codes and their causes. If the PCM stores the P1443 code alongside other codes that follow it, such as P1444 and P1445, then P1443 is the cause of the other two.

In case there are other codes that precede the p1443 code, then they may are the results of another cause. You will need to fix those prior codes first before tackling the p1443 code.

Resolve any stored code that precedes the p1443 code before proceeding to the next step.

Step 2

Use the vehicle manual to locate the EVAP system and thereby to locate the purge control valve. Take keen note of the interconnecting connectors, hoses, and wiring.

Perform an intensive visual inspection of the interconnecting wiring, connections, and hoses. Check for burns, cracks, corrosion, and splits.

Perform the necessary repairs on any damaged wiring, hoses, and connections. Rescan by using the scan tool to see if the code is still stored.

Step 3

If you see the code return, proceed to check for any poor electrical connection on all the interconnecting wiring. You will perform ground, resistance, and continuity checks on these wiring. This is the step where you will have to use the digital multimeter.

The vehicle manual has a specified value for the input voltage, which you should note while performing this check.

Consult the manual on how to perform the resistance, ground, and continuity checks for your car specifically.

You must always remember to disconnect the purge control valve from the powertrain control module during resistance and continuity checks. This is to prevent the controller from being damaged by the process.

Make the necessary repairs if you find any diversions. Recheck the input voltage again to see if the repairs solved the issue. Go ahead and proceed to compare the control valve resistance to the one on the manual and replace the valve if the values do not match.

Step 4

At this point, fixing the wiring, connection and circuits may have proven futile. Proceed to diagnose the purge control valve, which the high temperatures and engine vibrations may damage to.

You can use a digital multimeter and a voltage tester for this step. This will require you to disconnect the valve from the assembly. Alternatively, you can substitute the two tools for an OEM equivalent scanner with control functions to automatically perform the diagnosis. Performing the test manually will, however, increase the ease of performing the next procedure.

Apply direct current to the solenoid controlling the valve to confirm if it reacts to input voltage. Compare the recorded voltage to the one specified on the manual to make sure that the electrical side is in good shape.

For the next procedure, disconnect the purge control valve from the assembly, that is, if you had performed the last procedure automatically. Connect the vacuum pump to the valve and take note of the vacuum registered by the gauge.

For normal operation, the vacuum should hold almost indefinitely. Proceed to apply current across the valve again, and a notice of the vacuum decays immediately.

In case the vacuum begins to decay immediately after you have used the vacuum pump, then the valve is broken and needs a replacement. Moreover, if the vacuum does not decay once you apply a current to it, then the valves are broken too and need replacement.

Replace the valve, clear all codes and use the vehicle for at least one complete drive cycle. Use the scanner to monitor the EVAP system components’ performance in real-time.

Changing the valve will most likely fix the issue. If it does not, then checking for intermittent faults may provide a better solution since PCM failures are rare. In case all the intermittent faults (which are hard and time-consuming to diagnose) lead nowhere, then checking the PCM would be the only last resort option.

Other Codes Related To The P1443 Ford Code

  1. P1444 – Purge Flow Sensor Circuit Input Low.
  2. P1445 – Purge Flow Sensor Circuit High Condition.

Final Thoughts

There are no drivability concerns for this code. You should be safe to drive your car since the EVAP system only deals with emissions and has nothing to do with engine performance.

However, it is always recommended to fix any DTCs before they cause more problems.

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