C0651 Diagnostic Trouble Code

C0651 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 C0651 diagnostic trouble code may include:

Vacuum leak on the engine
Reduction in engine performance, especially at low RPM levels
Engine surge
Diminished fuel efficiency

Possible Causes :

Faulty IMRC actuator/sensor
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

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. 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. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code C0651 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 C0651.

Fortunately, C0651 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0651 Trouble Code For Specific Cars

C0651 Holden Barina Pedal Forward / Rearward Potentiometer Feedback Circuit Short to Battery
C0651 Chrysler Six Exhaust Gas Recirculation Sensor B Circuit High
C0651 Pontiac Grand Prix Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 1)
C0651 Claveau Descartes Fuel Rail/System Pressure - Too Low
C0651 Cadillac V16 Disable Signal Output Circuit Short to Battery
C0651 Oldsmobile Recon Damper LF Circuit Failure
C0651 Alvis Ta14 Air Mixture Solenoid Circuit Malfunction