B2109 Diagnostic Trouble Code

B2109 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a B2109 diagnostic trouble code may include:

Poor acceleration
Cherry red hot catalytic converter
Possible spark knock (detonation / pre-ignition)
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.

Repair Processes :

If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground.

Process Tips

Diagnostic trouble code B2109 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before B2109.

Fortunately, B2109 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B2109 Trouble Code For Specific Cars

B2109 Bristol 412 Crankshaft Position Camshaft Position Correlation (Bank 2 Sensor B)
B2109 Mercedes-benz Bionic Air Conditioner Refrigerant Charge Loss
B2109 Hillman Sporting PATS Transceiver Module Signal Is Not Received
B2109 Volkswagen Fusca Ride Control LF Shock Actuator Circuit Short To Ground
B2109 Fiat 10-12 Kickdown Hold Relay Open or Short Circuit to Ground
B2109 Bmw Cls Climate Control Recirculation Actuator Out of Limits
B2109 Mercedes E 350 Accelerate Warmup Solenoid Circuit Malfunction