U279A Diagnostic Trouble Code

U279A is a kind of OBD-II Diagnostic U-Network 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 U279A diagnostic trouble code may include:

Fuel pressure too high
Diminished fuel efficiency
Rich or lean exhaust
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Faulty IMRC actuator relay (if equipped)

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code U279A 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 U279A.

Fortunately, U279A is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U279A Trouble Code For Specific Cars

U279A Nissan Leopard Column Reach Feedback Potentiometer Circuit Short to Ground
U279A Nissan Stagea Cruise Control/Brake Switch A Circuit High
U279A Alfa Romeo Rm Air Bag Crash Sensor #1 Ground Circuit Short To Ground
U279A Abarth 600 A Camshaft Position - Timing Over-Advanced or System Performance (Bank 1)
U279A Mitsubishi Galant Autolamp Delay Increase Circuit Failure
U279A Bugatti Type 41 Cylinder 10 Misfire Detected
U279A Jaguar 420 Seat Driver Backward Circuit Short To Ground