Worn or faulty spark plug on cylinder 5; Faulty ignition coil or coil connector on cylinder 5; Faulty, blocked or leaking fuel injector on cylinder 5; Damaged wiring or poor connection to the cylinder 5 injector or coil; Vacuum or intake leak affecting cylinder 5, such as a split intake gasket or hose; Low compression in cylinder 5 from a valve, piston ring or head gasket fault; Fault in the ECU driver circuit for cylinder 5.

P0275

Cylinder 5 Contribution/Balance.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
75: FaultThe specific fault in that area

What it means

P0275 means the engine control unit has found that cylinder 5 is not contributing the same amount of power as the other cylinders. It sets when the cylinder balance or contribution test, based on crankshaft speed variation or a similar method, shows cylinder 5 is weaker or stronger than expected. The generic definition does not say why, so the root cause could be in the ignition, fuel, air or mechanical side of that cylinder.

Symptoms

Rough idle or engine shake
Misfire or hesitation under load
Reduced power and poor acceleration
Increased fuel consumption
Engine management light on, possibly flashing under heavy misfire
Rough or uneven running at cold start

Possible causes

Worn or faulty spark plug on cylinder 5likely
Faulty ignition coil or coil connector on cylinder 5likely
Faulty, blocked or leaking fuel injector on cylinder 5likely
Damaged wiring or poor connection to the cylinder 5 injector or coilpossible
Vacuum or intake leak affecting cylinder 5, such as a split intake gasket or hosepossible
Low compression in cylinder 5 from a valve, piston ring or head gasket faultpossible
Fault in the ECU driver circuit for cylinder 5rare

How to diagnose

Read all stored codes and freeze frame data, noting engine load, speed and temperature when the fault set, and check for related misfire or fuel trim codes.
Confirm which physical cylinder is number 5 for this engine, as the firing order and cylinder numbering depend on the model and engine.
Inspect the cylinder 5 coil, connector, injector connector and wiring for damage, corrosion, oil or heat damage.
Remove and inspect the cylinder 5 spark plug for wear, fouling or damage, and compare it with the other cylinders.
Swap the cylinder 5 coil with another cylinder, clear the codes and see whether the fault follows the coil.
Check the injector electrically and by listening or measuring the operation, then compare against another cylinder; check the fuel trims and live misfire counters.
Smoke test or inspect the intake system for leaks near cylinder 5.
Carry out compression and leak-down tests on cylinder 5 if ignition, fuel and air supply all check out.

How to fix

Replace the spark plugs, as a set where the service schedule calls for it.
Replace the faulty ignition coil or repair its connector.
Clean or replace the faulty fuel injector, following the manufacturer's procedure for the engine.
Repair damaged wiring or connectors in the cylinder 5 circuits.
Repair intake leaks by replacing the faulty gasket, hose or seal.
Carry out the necessary engine mechanical repair if compression is low, such as valve or piston ring work.

Can I keep driving?

Medium severity

The car can usually be driven gently for a short time to get it to a workshop, but should be fixed soon. If the engine light flashes or the engine runs very roughly, stop driving, as unburnt fuel can damage the catalytic converter.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.