C12E4 Diagnostic Trouble Code

C12E4 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 C12E4 diagnostic trouble code may include:

Malfunction Indicator Lamp (MIL) illuminated
Carbon Buildup on O2 Sensor
Poor fuel economy
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 :

A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Faulty IMRC actuator/sensor
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C12E4 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 C12E4.

Fortunately, C12E4 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C12E4 Trouble Code For Specific Cars

C12E4 Arab 2-litre Air Suspension LR Air Spring/Shock Solenoid Output Circuit Open
C12E4 Alpine A108-904 Air Bag Passenger Circuit Failure
C12E4 Leblanc Caroline TCM Communication Circuit
C12E4 Ford B-max Liftgate Disarm Switch Circuit Short to Ground
C12E4 Autovia V8 Aux Heater Glow Plug Circuit Open
C12E4 Maserati Mistral Transmission Fluid Pressure Sensor/Switch F Circuit Range/Performance
C12E4 Ferrari 375 Intake Air Temperature Circuit Range/Performance Problem