Faulty ignition coil or spark plug on cylinder 9; Faulty or blocked fuel injector on cylinder 9, or a fault in its wiring; Damaged wiring or poor connector contact to the cylinder 9 injector or coil; Vacuum or intake air leak affecting cylinder 9; Low compression on cylinder 9 (worn rings, burnt valve, head gasket leak); Fault in the engine control unit driver circuit for cylinder 9.

P0287

Cylinder 9 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)
87: FaultThe specific fault in that area

What it means

P0287 is the generic code for a fault in the cylinder 9 contribution or balance circuit, meaning the engine control unit has judged that cylinder 9 is not contributing its fair share of power compared with the other cylinders. It usually sets after the control unit sees crankshaft speed variation or a cylinder balance test result outside the expected limit for that cylinder. The code only applies to engines with nine or more cylinders, so the exact test method and cylinder numbering depend on the model and engine.

Symptoms

Rough running or a noticeable misfire, especially at idle
Loss of power and flat acceleration
Engine management warning light on, possibly flashing under load
Increased fuel consumption
Engine vibration or uneven idle
Possible smell of unburnt fuel from the exhaust

Possible causes

Faulty ignition coil or spark plug on cylinder 9likely
Faulty or blocked fuel injector on cylinder 9, or a fault in its wiringlikely
Damaged wiring or poor connector contact to the cylinder 9 injector or coilpossible
Vacuum or intake air leak affecting cylinder 9possible
Low compression on cylinder 9 (worn rings, burnt valve, head gasket leak)rare
Fault in the engine control unit driver circuit for cylinder 9rare

How to diagnose

Read all stored and pending codes and the freeze frame data to see engine speed, load and temperature when the code set; check for related misfire codes
Confirm which physical cylinder is cylinder 9 using the manufacturer's firing order and cylinder numbering for that engine
Inspect the wiring and connectors to the cylinder 9 coil and injector for damage, corrosion, heat or fluid contamination
Check the spark plug on cylinder 9 for wear, fouling or damage, and compare with the other cylinders
Swap the cylinder 9 coil with a neighbouring cylinder and see whether any misfire moves with it
Check the injector operation, using resistance and signal checks, and compare against the specification for that engine
Smoke test or inspect the intake system for leaks near cylinder 9
Carry out a compression or leak-down test on cylinder 9 if ignition and fuel checks are good

How to fix

Replace the faulty ignition coil or spark plug on cylinder 9, and consider replacing the plugs as a set
Clean or replace the faulty fuel injector on cylinder 9
Repair or replace damaged wiring or connectors in the affected circuit
Repair intake leaks by replacing faulty gaskets, seals or hoses
Carry out the necessary mechanical engine repair if compression is low
Diagnose and repair or replace the control unit only after all other causes have been ruled out

Can I keep driving?

Medium severity

The car can be driven gently for a short time to get it to a workshop, but avoid heavy loads and high revs. Persistent misfires can damage the catalytic converter and the engine, so have it fixed soon, and stop driving if the warning light flashes.

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