C251D Diagnostic Trouble Code

C251D 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 C251D diagnostic trouble code may include:

Diminished fuel efficiency
Fuel pressure too high
Malfunction Indicator Lamp (MIL) illuminated
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
Faulty IMRC actuator/sensor

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. 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. 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.

Process Tips

Diagnostic trouble code C251D 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 C251D.

Fortunately, C251D is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C251D Trouble Code For Specific Cars

C251D Porsche Boxster Type 987 Fuel Pressure Regulator 1 Performance
C251D Morgan 42 F4 Booster Solenoid circuit Failure
C251D Volvo Xc90 SCP (J1850) Invalid or Missing Data for Function Read Fuel System
C251D Daf 55 Gear Lever X Position Circuit Intermittent
C251D Bugatti Eb218 Cylinder #5 High To Low Side Short
C251D Paterson Model 33 Driver Side Satellite Communication Circuit Short to Ground
C251D Chrysler Le Baron Evaporative Emission Control System Pressure Sensor Malfunction