Cylinder 9 Contribution/Balance Fault
The P0287 code indicates that the Engine Control Module (ECM) has detected a misfire or imbalance in cylinder 9's power contribution compared to other cylinders. This is typically caused by issues with fuel delivery, ignition, or mechanical compression. The ECM monitors crankshaft speed variations to identify weak cylinders.
01. Most Common Causes
- Faulty fuel injector on cylinder 9
- Ignition coil or spark plug failure on cylinder 9
- Low compression in cylinder 9 (e.g., worn piston rings, valve issues)
- Wiring or connector problems to injector or coil
- Vacuum leak affecting cylinder 9
02. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Reduced power and acceleration
- Poor fuel economy
- Possible engine vibration
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect spark plug and ignition coil on cylinder 9; swap with another cylinder to see if misfire follows.
Step 3: Perform a fuel injector balance test or swap injector to check for change.
Step 4: Check compression on cylinder 9; compare to others.
Step 5: Inspect wiring and connectors for damage or corrosion.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the misfire can damage the catalytic converter and cause further engine issues. Short trips to a repair shop are acceptable if the engine is not overheating or severely misfiring.
How much does it cost to fix?▼
Costs vary: replacing a spark plug or coil is $50-$150; a fuel injector replacement is $200-$500; compression repairs can exceed $1,000. Diagnostic fees are typically $100-$150.