P118D Diagnostic Trouble Code

P118D 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 P118D diagnostic trouble code may include:

Cherry red hot catalytic converter
Poor acceleration
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs. 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 P118D 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 P118D.

Fortunately, P118D is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P118D Trouble Code For Specific Cars

P118D Aston Martin V12 Air Suspension Warning Lamp Circuit Failure
P118D Moretti Panoramica Boost Calibration Fault
P118D Volkswagen New Beetle Right Rear Sensor Circuit Failure
P118D Kia All-new Seat Rear Up/Down Potentiometer Feedback Circuit Failure
P118D Porsche 928 Fuel Delivery System Malfunction - Low
P118D Rover Alvis Ignition Coil D Secondary Circuit Malfunction
P118D Marcos 850 Transfer Case Contact Plate "D" Encoder Circuit Failure