OBD codes / P0286
P0286
ModerateCylinder 9 Injector Circuit High
Ten or eleven healthy cylinders will keep the car feeling normal, but the unburned fuel from an erratic cylinder 9 still risks overheating that bank's catalytic converter. Schedule the repair promptly regardless of how smooth the engine feels, and park it if the light flashes.
What this code means
Exclusive to engines with nine or more cylinders — V10s and V12s among production cars — P0286 sets when the ECM detects voltage above the expected range on the cylinder 9 injector control circuit. The high-side fault signatures are a short to battery voltage in the harness, or added resistance from a corroded connector, deteriorated terminal, or an injector winding that has failed open. Circuit codes like this one specifically implicate the electrical path; a mechanically clogged injector would misfire without ever tripping the circuit monitor, so cleaning additives are the wrong tool here. Comparison against the engine's many healthy injector circuits makes diagnosis efficient, and a swap test gives a definitive answer. P0209 (circuit) and P0309 (misfire) are the related codes for this cylinder. Because manufacturers number V10/V12 banks differently, confirm which physical cylinder is number 9 before you start.
Symptoms you might notice
- Cylinder 9 misfire, often barely perceptible on a V10/V12
- Loss of the engine's characteristic smoothness
- Slightly reduced power and economy
- Check-engine light; flashing means an active misfire
- Code may store with no felt symptoms when intermittent
What it costs to fix
Typical range: $60–$450 · about ~0.5–2 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Fuel injector (single) | $50–$300 | ~0.5–2 hrs |
| Wiring/connector repair | $5–$50 | ~0.5–2 hrs |
On V10 and V12 engines the labor dominates: injectors are packed under intake plumbing and access is slow, so even a simple repair can hit the top of the labor range. Direct-injection injectors for these engines also exceed typical parts pricing.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0286 for my exact vehicle →
Frequently asked
What engines actually get P0286?
Only those with at least nine cylinders — in production vehicles, V10 and V12 engines. The code names cylinder 9's injector circuit specifically, and where cylinder 9 physically sits depends on the manufacturer's bank-numbering convention.
High versus low — why does the direction matter?
It narrows the fault list. High voltage (P0286) points to an open circuit, resistance from corrosion, or a short to battery voltage. Low voltage (P0285) points to a short to ground or a shorted injector coil. Knowing the direction saves diagnostic time on an engine where access is slow.
Would an injector-cleaning service help?
No. P0286 reports an electrical fault in the circuit driving the injector, and cleaning targets fuel deposits inside the nozzle. The repair lies in the connector, harness, injector winding, or rarely the ECM — not in the fuel system.
Can I drive it until service?
Short, unhurried trips with a steady light are generally acceptable. The hidden cost of waiting is catalyst damage from unburned fuel, which on a V10/V12 with multiple converters gets expensive fast. A flashing check-engine light means stop driving.
Seeing P0286 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0286 for my vehicleRelated trouble codes
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Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.