P0878 Diagnostic Trouble Code

P0878 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 P0878 diagnostic trouble code may include:

Hesitation upon acceleration
Excessive exhaust leak
Rich or lean exhaust
Reduction in engine performance, especially at low RPM levels

Possible Causes :

A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
Some aftermarket accessories and performance modifications
Dirty air cleaner element Damaged DPF

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. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code P0878 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 P0878.

Fortunately, P0878 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0878 Trouble Code For Specific Cars

P0878 Austin A60 Autolamp Delay Increase Circuit Short To Ground
P0878 Chevrolet Ssr Electrodrive Fan 2 Operational Failure (Passenger Side)
P0878 Datsun 15 High Clutch Drum Speed Sensor Intermittent
P0878 Talbot Avenger Mirror Passenger Horizontal Switch Circuit Failure
P0878 Chevrolet Monte Carlo EGI Temperature Sensor Failure
P0878 Reliant Se6 Gate Select Position Circuit High
P0878 Venturi 400 Pump Rotor Control Underfueling