C0494 Diagnostic Trouble Code

C0494 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 C0494 diagnostic trouble code may include:

Rich or lean exhaust
Fuel pressure too low
Engine surge
Poor acceleration

Possible Causes :

Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.
Faulty IMRC actuator relay (if equipped)

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 C0494 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 C0494.

Fortunately, C0494 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0494 Trouble Code For Specific Cars

C0494 Chevrolet Impala Dynamic Stability Control Left Front Valve Malfunction
C0494 Ogle Sx Cylinder 3 Misfire Detected
C0494 Ford Consul MAF Sensor In Range But Higher Than Expected
C0494 Mercedes Clk 240 ABS Outlet Valve Coil LR Circuit Open
C0494 Seat Leon 2 Injector Control Pressure System Fault
C0494 Volkswagen New Beetle Right Rear Sensor Circuit Failure
C0494 Nsu Autonova Cylinder 11 Injector Circuit High