Cylinder 6 Contribution/Balance Fault
The P0278 code indicates that the Engine Control Module (ECM) has detected a lack of contribution or a power imbalance from cylinder 6. This means cylinder 6 is not firing as efficiently as the other cylinders, causing a rough idle, misfire, or reduced engine performance. The ECM monitors crankshaft speed variations to identify weak cylinders.
01. Most Common Causes
- Faulty fuel injector on cylinder 6
- Worn spark plug or ignition coil on cylinder 6
- Low compression in cylinder 6
- Vacuum leak affecting cylinder 6
- Engine mechanical issue (e.g., burnt valve, broken piston ring)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced power and acceleration
- Poor fuel economy
- Engine vibration at idle
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 6; swap with another cylinder to see if misfire follows.
Step 3: Perform a fuel injector balance test or swap injectors to isolate the issue.
Step 4: Check compression on cylinder 6; compare to other cylinders.
Step 5: Inspect for vacuum leaks and wiring issues to the injector or coil.
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 reduce engine performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Costs vary: a spark plug replacement is around $50-$150, an ignition coil $100-$200, and a fuel injector $150-$400. Diagnosis fees are typically $100-$150.