U278D Diagnostic Trouble Code

U278D 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 U278D 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 :

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.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code U278D 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 U278D.

Fortunately, U278D is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U278D Trouble Code For Specific Cars

U278D Datsun Bluebird HO2S Heater Control Circuit (Bank 1 Sensor 1)
U278D Reliant Se6 Gate Select Position Circuit High
U278D Honda Civic Type-r Pressure Control Solenoid Failed Low
U278D Bmw S3 Clutch Position Control Error
U278D Morris Ten Four Cam Calibration Fault
U278D Jaguar C-type Seat Driver Forward Circuit Open
U278D Mitsubishi L300 Autolamp Sensor Input Circuit Short To Battery