C0256 Diagnostic Trouble Code

C0256 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 C0256 diagnostic trouble code may include:

Engine surge
Blown fuse (if applicable)
Lack of power
Hesitation upon acceleration

Possible Causes :

Some aftermarket accessories and performance modifications
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.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Repair Processes :

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. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve.

Process Tips

Diagnostic trouble code C0256 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 C0256.

Fortunately, C0256 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0256 Trouble Code For Specific Cars

C0256 Volvo C70 SCP (J1850) Invalid or Missing Data for Engine RPM
C0256 Ford Five Hundred Mirror Driver Down Circuit Failure
C0256 Fuldamobil S7 O2 Sensor Circuit High Voltage (Bank 2 Sensor 1)
C0256 Panther Lima Driver Sid, Side mount Airbag Circuit Short to Ground
C0256 Fiat Ulysse Left Front Vertical Accelerometer Circuit Failure
C0256 Tvr V8 Power Steering Pressure Sensor Circuit Range/Performance
C0256 Great Wall Florid Passenger Rear Seat Down Switch Circuit Short to Battery