C0018 Diagnostic Trouble Code

C0018 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 C0018 diagnostic trouble code may include:

Rich or lean exhaust
Fuel pressure too low
Engine surge
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 relay (if equipped)

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. Now, clear the codes and test-drive the vehicle to see if the code is reset. 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 C0018 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 C0018.

Fortunately, C0018 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0018 Trouble Code For Specific Cars

C0018 Mercedes Cls 500 ABS Outlet Valve Coil RR Circuit Failure
C0018 Simca 1500 Intake Valve Control Solenoid Circuit High (Bank 1)
C0018 Rover P5 Ignition Control (IC) Circuit Low Voltage
C0018 Daihatsu Atrai Gear Shift Foward Actuator Circuit Range/Performance
C0018 American Traveler Air Suspension LF Air Spring Solenoid Output Circuit Open
C0018 Maserati Barchetta Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance
C0018 Ac 15 A/C Refrigerant Temperature Circuit Range/Performance