C0851 Diagnostic Trouble Code

C0851 is a kind of OBD-II Diagnostic C-Chassis 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 C0851 diagnostic trouble code may include:

Misfire
Misfire
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Reduction in engine performance, especially at low RPM levels

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code C0851 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 C0851.

Fortunately, C0851 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0851 Trouble Code For Specific Cars

C0851 Hillman Speed PATS Received Invalid Format Of Key-Code From Ignition Key Transponder
C0851 Opel Trixx Door Handle Switch Circuit Failure
C0851 Turcat-mery 14 Pedal Forward / Rearward Potentiometer Feedback Circuit Short to Battery
C0851 Holden Hz Power Sliding Door On/Off Switch Open Circuit
C0851 Bugatti Type 50 Cylinder 12 Contribution/Balance Fault
C0851 Bmw Wartburg Code Word Unregestered
C0851 Toyota Hilux Oil Level Lamp Circuit Open