Fault codeP0278

SEVERE

Cylinder 6 Contribution/Balance Fault

What this code means

Cylinder 6 Contribution/Balance Fault.

P0278 is a generic code: it means the same thing on every make. P0278 belongs to family P02xx — Injector circuit. Its page explains how to read a code and groups all its codes by part.

Cylinder contribution (injector balance)

The control unit watches how much each cylinder speeds up the crankshaft at every combustion. If one cylinder contributes noticeably less or more than the others, it records a balance fault for that cylinder. These codes mostly concern diesel engines.

What you notice

Shaking at idle, uneven running, hesitation, sometimes smoke or a smell of diesel.

How to check it

The injector of the cylinder concerned is the main suspect: leak-off test, cleaning or flow measurement in a workshop. A compression test rules out a mechanical cause (valve, piston ring). Check the injector's wiring and connector too.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Engine RPM
Engine fuel rate
Fuel injection timing

What to do

Have it checked promptly. An injection, fuel-supply or boost fault can cost power, cause misfires and eventually damage the engine or the catalytic converter. If the light is flashing or the engine is overheating, stop driving.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
2Injector circuit
78P0278