P04D8 Diagnostic Trouble Code

P04D8 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 P04D8 diagnostic trouble code may include:

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
Faulty or damaged wiring
Hesitation upon acceleration
Rich or lean exhaust

Possible Causes :

Faulty IMRC actuator relay (if equipped)
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble. 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.

Process Tips

Diagnostic trouble code P04D8 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 P04D8.

Fortunately, P04D8 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P04D8 Trouble Code For Specific Cars

P04D8 Fso Polonez O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
P04D8 De Tomaso Guara HPU (Hydraulic Pump Unit) Pressurisation Failure
P04D8 Suzuki C2 Memory 2 Switch Circuit Short To Battery
P04D8 Ford Ka 2 Mirror Driver Right Circuit Short To Battery
P04D8 Hupmobile 621 Rotor Control Fault
P04D8 Matra-simca D Jet Transmission Neutral Safety Switch Short Circuit To Ground
P04D8 Mercedes-benz Ck Class Air Mixture Solenoid Circuit Malfunction