P0666 Diagnostic Trouble Code

P0666 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 P0666 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Diminished fuel efficiency

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 :

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

Process Tips

Diagnostic trouble code P0666 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 P0666.

Fortunately, P0666 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0666 Trouble Code For Specific Cars

P0666 Chevrolet Omega EGR Metering Orifice Restricted
P0666 Mg Rv Air Temperature External Sensor Circuit Open
P0666 Lexus Flv TCM Power Input Signal Low
P0666 Dodge Shadow Ignition Spare
P0666 Porsche Gt Fuel Pump Primary Circuit Malfunction
P0666 Nissan Juke Coast Clutch Solenoid Inductive Signature Malfunction
P0666 Sunbeam 12 MAF Sensor Out Of Self Test Range./KOER Not Able To Complete KOER Aborted