P118A Diagnostic Trouble Code

P118A 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 P118A 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 :

If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for. 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. Look at the plug wires to make sure they are not burnt or laying on the exhaust.

Process Tips

Diagnostic trouble code P118A 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 P118A.

Fortunately, P118A is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P118A Trouble Code For Specific Cars

P118A Lancia Scorpion SSPOD Open Circuit or Closed Circuit Fault
P118A Nissan Qashqai Crankshaft Position Camshaft Position Correlation (Bank 2 Sensor B)
P118A Riley Redwing Hydraulic Fluid Pressure/ Flow Circuit Failure
P118A Mercury Sable Air Suspension Reservoir Pneumatic Failure
P118A Austin 12 Audio Reverse Aid Mute Input Ckt Failure
P118A Rolls-royce Park Ward Hydraulic Pump Relay Circuit High
P118A Mercedes Clc ABS Outlet Valve Coil LF Circuit Open