C279F Diagnostic Trouble Code

C279F 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 C279F diagnostic trouble code may include:

Faulty or damaged wiring
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
Poor fuel economy
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

An air leak forward of the DPF will change the sensor readings resulting in the code
Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. 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 C279F 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 C279F.

Fortunately, C279F is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C279F Trouble Code For Specific Cars

C279F Spyker 12 Lamp Brake Warning Output Circuit Short To Ground
C279F Jaguar F-type Seat Driver Forward Switch Circuit Short To Battery
C279F Daewoo Arcadia Fuel Trim Malfunction (Bank 1)
C279F Renault Talisman HO2S Heater Control Circuit (Bank 2 Sensor 1)
C279F Hongqi Ca RF CORNER LAMP OUTPUT Ckt Short to Battery
C279F Sheffield-simplex 30 Insufficient RMP Increase During Spark Test
C279F Mercedes Cls 400 ABS Outlet Valve Coil RF Circuit Short To Ground