C20D4 Diagnostic Trouble Code

C20D4 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 C20D4 diagnostic trouble code may include:

Excessive exhaust leak
Hesitation upon acceleration
Malfunction Indicator Lamp (MIL) illuminated
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.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. 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. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio.

Process Tips

Diagnostic trouble code C20D4 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 C20D4.

Fortunately, C20D4 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C20D4 Trouble Code For Specific Cars

C20D4 Adler 12 ABS Inlet Valve Coil RF Circuit Short To Ground
C20D4 Seat Formula Injector Control Circuit
C20D4 Pontiac Salsa Flash To Pass Switch Circuit Failure
C20D4 Nissan Patrol Cooling Fan 1 Control Circuit Malfunction
C20D4 Mercedes S 320 Additional Fan Relay Circuit Malfunction
C20D4 Maserati Levante Transmission Fluid Pressure Sensor/Switch F Circuit
C20D4 Rochet-schneider 30 Hydraulic Pressure Sensor Circuit Low Input