EngineCritical✅ DIY Friendly

P0309

P0309 means: Cylinder 9 Misfire Detected. The engine control module has detected a misfire on cylinder 9 (V8/V10 engines only).

Cylinder 9 Misfire Detected

The engine control module has detected a misfire on cylinder 9 (V8/V10 engines only).

SeverityCritical

CategoryEngine

Est. Repair Cost$150-$400

Code TypePowertrain

DIY RepairYes

💡 Pro Tip: On engines with cylinder 9, always confirm your engine's exact cylinder numbering diagram since it varies by manufacturer.

What does OBD2 code P0309 mean?+

P0309 stands for Cylinder 9 Misfire Detected. The engine control module has detected a misfire on cylinder 9 (V8/V10 engines only).

What causes code P0309?+

Faulty spark plug or coil; Fuel injector issue; Low compression; Vacuum leak

How do I fix code P0309?+

Inspect spark plug and coil for cylinder 9; Test injector operation; Perform compression test; Replace faulty component

How much does it cost to fix P0309?+

Estimated repair cost for P0309 is $150-$400.

Is P0309 DIY-friendly?+

Yes — P0309 is generally DIY-friendly with basic tools.