P04C9 Diagnostic Trouble Code

P04C9 is a kind of OBD-II Diagnostic P-Powertrain 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 P04C9 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly

Possible Causes :

Defective ECU strategies or components will prevent proper regeneration
The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. 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. Look at the plug wires to make sure they are not burnt or laying on the exhaust.

Process Tips

Diagnostic trouble code P04C9 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 P04C9.

Fortunately, P04C9 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P04C9 Trouble Code For Specific Cars

P04C9 Ginetta G33 OSS Circuit Intermittent Malfunction
P04C9 Puma Gtb Fuel Temperature Sensor #1 Circuit Short to Ground
P04C9 Tracta Tracta Passenger Side Airbag Fault
P04C9 Zagato Bravo
P04C9 Mg Magnett Air Suspension RR Vent Request Exceeded Max Timing
P04C9 Fiat Doblo Lamp Park Input Circuit Failure
P04C9 Buick Blackhawk Cylinder 5 Misfire Detected