P0287
Cylinder 9 Contribution/Balance
When a vehicle powertrain module registers the fault code P0287, it points directly to an internal system malfunction identified as "Cylinder 9 Contribution/Balance". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
When your OBD2 scanner shows P0287, the engine control module has flagged an issue specifically related to cylinder 9 contribution/balance. Typical symptoms include engine stumble, rough acceleration, loss of power. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Engine stumble, rough acceleration, loss of power
Common Causes
- Bad fuel injector on Cyl 9
- Low cylinder compression
- Ignition system failure
- Mechanical engine damage
How to Fix
- 1 Replace fuel injector
- 2 Perform compression test
- 3 Diagnose ignition system
- 4 Inspect engine internals
Technical Explanation
Code P0287 is confirmed when the ECM's diagnostic algorithm detects a parameter deviation that persists across a defined number of consecutive drive cycles. For injector-specific codes, the ECM monitors the injector control circuit voltage drop during each pulse; a shorted or open injector presents a characteristic resistance signature that differs measurably from a healthy unit. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
Driving with an active P0287 fault risks accelerating damage to bad fuel injector on cyl 9 and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
When diagnosing P0287, always test fuel volume delivery in addition to static pressure — a pump that holds pressure at idle but delivers insufficient volume under load will cause the fault only during acceleration or high demand, making it difficult to replicate in the driveway. Use a fuel pressure gauge with a volume outlet port: a healthy pump should deliver at least 1 liter per minute. Replace the fuel filter first; it's the cheapest test and solves the fault in a significant percentage of cases.
Injector: 200 - 500; Engine work: 1,500+