C1003 Diagnostic Trouble Code

C1003 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 C1003 diagnostic trouble code may include:

Fuel pressure too low
Rich or lean exhaust
Diminished fuel efficiency
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.
Faulty IMRC actuator/sensor

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. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code C1003 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 C1003.

Fortunately, C1003 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1003 Trouble Code For Specific Cars

C1003 Rover City Rover Ignition Coil H Primary/Secondary Circuit Malfunction
C1003 Vauxhall Viscount Pressure Control Solenoid Performance or Stuck Off
C1003 Cadillac Evoq Decklid Release Circuit Open
C1003 Ford Granada Mirror Driver Left Circuit Open
C1003 Volkswagen Magellan Right Rear Center Sensor Circuit Failure
C1003 Nobel 200 Cylinder 1 Injector Circuit Low
C1003 Alvis Te Air Suspension Disable Switch Circuit Short To Ground