P12B8 Diagnostic Trouble Code

P12B8 is a kind of OBD-II Diagnostic P-Powertrain 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 P12B8 diagnostic trouble code may include:

Corroded or damaged connector
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Lack of power
Engine surge

Possible Causes :

Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
An air leak forward of the DPF will change the sensor readings resulting in the code
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

Repair Processes :

If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code P12B8 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 P12B8.

Fortunately, P12B8 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P12B8 Trouble Code For Specific Cars

P12B8 Austin-healey Sports Aux Blower Sense Switch Circuit Failure
P12B8 Italdesign Legram SCP (J1850) Lack of Acknowledgment for Audible Warnings
P12B8 Ford Sportka Mirror Passenger Up Circuit Failure
P12B8 Toyopet Crown Motor Temperature Out of Range
P12B8 Ford Explorer Memory 2 Switch Circuit Failure
P12B8 Nissan Almera Climate Control A/C Pressure Switch Circuit Failure
P12B8 Nissan S-cargo Cruise Control Accel Signal Malfunction