If you’re looking for all of the detailed information on OBD2, this article will be very useful. OBD stands for On-Board Diagnostics and it’s a diagnostic system used in every car.
OBD2 technology helps to better monitor your car’s systems and emissions to make sure that it is functioning correctly and that nothing is malfunctioning. OBD2 is essentially an updated version of older, more basic OBD systems
- 1 What is OBD2?
- 2 Why OBD2 Technology?
- 3 OBD2 Application
- 4 The 10 Modes of OBD2
- 5 Does My Car Have OBD-II?
What is OBD2?
Onboard diagnostic systems have been used in cars since the 1970s an 1980s to diagnose engine problems. These systems were primarily developed to meet the EPA emission standards to protect the environment from becoming polluted by car emissions.
Over the years OBD technology has become more advanced and standardized, which is where OBD2 comes into play. OBD2 is the same system required to be used by all car manufacturers to monitor and diagnose car issues and emissions.
Why OBD2 Technology?
OBD2 technology monitors more than just emissions, it looks at all engine functions, ABS breaks systems, SRS airbag systems, fuel economy and much more.
Because it is required to use the same interface for every car, it’s easy to find scan tools that allow you to read the data on your car. OBD2 provides a universal diagnosis and inspection process to make sure all cars are meeting emission and performance requirements.
OBD2 Diagnostic Connector
In the past, car manufacturers could create their own OBD systems, so they varied from one car model to the next. This made it hard to read diagnostic information from car to car, so a universal OBD2 diagnostic connector was established.
This connector is a 16-pin port. It is the same connector for every car, so reading OBD2 systems are much easier. However, not every car model or OBD scan tool uses all 16 of the pins to send and receive information.
While OBD2 connectors are all the same, different manufacturers use them differently. So for that reason, there are different protocols. The protocols are basically different ways that the connector can communicate with the OBD2 system in your car.
Modern vehicles use one of the 5 OBD2 protocols for communication. These protocols are ISO 15765-4/SAE J2480, SAE J1850 VPW, ISO9141-2, SAE J1850 PWM, and ISO14230-4 (KWP2000).
ISO 15765-4/SAE J2480
This is the most recent protocol, which was added in 2003, and is mandatory on all 2008 and later models sold in the US. It is also referred to as CAN-BUS. It uses pins 6 and 14 on the connector, as well as 4 and 5.
In this protocol, pin 2 must be used along with 4, 5, and 16. However, pin 10 won’t be there. This protocol is usually found in Asian cars.
You’ll most likely find this protocol in Chrysler vehicles, as well as European and Asian models too. However, it’s not used as much.
SAE J1850 VPW
In this protocol, pin 2 and pin 10 are used. It may also use 4,5 and 16. It’s usually used in Ford cars.
SAE J1850 PWM
This protocol has to use pin 2, and sometimes 4,5 and 16 are there as well. It’s most commonly found in GM vehicles.
OBD2 Codes / OBD2 PIDs
OBD2 codes, also called Parameter IDs (PIDs), are used to tell you what is going on in your vehicle. They are used to request data from your vehicle and can be read with a diagnostic scan tool.
There are tons of different codes, some are standard on all vehicles and some codes are specific to different models of cars. Some of the standard codes are P0171 System Too Lean (Bank 1) and P0440 Evaporative Emission Control System Malfunction.
In order to communicate with your car’s OBD system, you’ll need an application that plugs into the diagnostic connector and can translate the information for you. There are a few different application options that you can do this with
OBD2 Cable Scan Tools
These are the most basic type of scan tools that are handheld devices that connect to your car’s connector via cable. You plug them into the connector and the reader scans the codes and relays the information to you on the screen.
There is a wide range of cable scan tools, ranging from simple code readers to professional diagnostic tools. As the cable scan tool becomes more advanced, the price tends to increase. You can get a cable scan tool for as little as less than $100 or as expensive as $700 or more.
OBD2 Bluetooth Scanners
This is a new version of OBII applications that plug into your car’s connector and then send the information via Bluetooth to your phone or other Bluetooth devices.
You must use a corresponding OBD2 app on your device to be able to look at all the information that is communicated via the Bluetooth scanner.
This application is a very convenient and easy way to read the diagnostics on your car. Unlike the cable scan tools, the information is displayed with easy to understand explanations and graphs rather than just a set of codes.
OBD2 PC-based Software
You can also read the OBD2 information on your PC laptop. These applications are similar to handheld scan tools except they give you much more information and it’s easier to read the interface.
To do this, you can purchase and OBD2 adapter with a USB plug that goes into your laptop and then downloads the necessary software to read the information.
Data loggers are similar to OBD diagnostic tools, except that they record your car’s information such as vehicle speed, RPM, and throttle position, and then save it onto an SD card in CSV format.
You can also easily perform emission testing with OBD2. In the past, this was primarily done through tailpipe tests, which were not as accurate or fast. Now you can easily test your car’s emissions with an OBD2 scan tool.
Driver’s supplementary vehicle instrumentation
This is instrumentation that is installed on a vehicle in addition to the normal instrumentation provided by the car manufacturer.
These are gauges that show customizable data information to the driver during normal operation. These are similar to other scan tools but provide specific information that a driver chooses.
The 10 Modes of OBD2
There are 10 different modes used by OBDII systems that allow you to read the raw data. Not all vehicles support all modes.
This mode shows the current data in the system, such as engine speed, engine temperature, and vehicle speed.
This shows the freeze frame data of a fault, which is sensor data record instantaneously when a fault is detected. This allows you to see what was happening at the moment the fault occurred.
This mode shows the stored Diagnostic Trouble Codes (DTCs). These trouble codes are standard for all car makes and models and start with a letter followed by 4 digits.
There are 4 categories of codes: P0xxx, C0xxx, B0xxx, and U0xxx. P0xxx codes relate to the powertrain (which is the engine and transmission).
C0xxx codes have to do with the chassis, B0xxx codes have to do with the body, and U0xxx codes have to do with the communications network. This mode is the most commonly used.
This mode allows you to clear DTCs and stored data. You can reset the fault codes and erase any stored data.
In this mode, you can see the results of the oxygen sensor monitoring systems (for non-CAN systems only).
This mode shows the scan results of other sensors that are not required to be monitored continuously.
This mode shows you pending DTCs which have been detected during the current or previous driving cycle but aren’t confirmed.
This mode allows you to see self-diagnosis reports of other systems such as fuel pumps and idle valves.
This mode allows you to request vehicle information such as VIN and calibration values for your specific vehicle.
Mode 10 (Also called Mode A)
This gives you the permanent DTCs, which cannot be cleared like in modes 3 and 7. These stored DTCs can only be cleared after several driving cycles with no detection of the codes.
Does My Car Have OBD-II?
Although it may seem confusing to try to figure out if your car has OBDI or OBDII, it’s actually really quite simple. If your car was manufactured before 1995, it uses OBDI.
If it was manufactured starting in the 1995 or 1996 model year, then your car has OBD-II. Most vehicles have OBD-II unless it’s a very old model. So you will need an OBD-II diagnostic tool to be able to read your car’s diagnostic information.