C2791 Diagnostic Trouble Code

C2791 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 C2791 diagnostic trouble code may include:

Blown fuse (if applicable)
Engine surge
Reduction in engine performance, especially at low RPM levels
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.
Dirty air cleaner element Damaged DPF

Repair Processes :

Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble. 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.

Process Tips

Diagnostic trouble code C2791 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 C2791.

Fortunately, C2791 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C2791 Trouble Code For Specific Cars

C2791 Volkswagen 1-litre Rear Fog Lamp Switch Circuit Failure
C2791 Renault 14 Gear 1 Incorrect ratio
C2791 Acura Arta ABS Hydraulic Pressure Differential Switch Input Circuit Failure
C2791 Suzuki Fronte
C2791 Austin Seven Aux A/C Blower Speed 2 Circuit Short to Ground
C2791 Volvo V60 SCP (J1850) Invalid or Missing Data for External Access (Doors)
C2791 Skoda 120 KAM Voltage Too Low