Cylinder 6 Fuel Trim at Min Limit
The P02AF code indicates that the engine control module (ECM) has detected that the fuel trim for cylinder 6 has reached its minimum limit, meaning the system is trying to reduce fuel delivery as much as possible. This typically occurs when the air-fuel mixture is too rich, and the ECM is unable to lean it out further. Common causes include a stuck-open fuel injector, a faulty oxygen sensor, a vacuum leak, or a mechanical issue like low compression. This condition can lead to poor fuel economy, rough idle, and potential catalytic converter damage if not addressed.
01. Most Common Causes
- Stuck open fuel injector on cylinder 6
- Faulty oxygen sensor (pre-cat)
- Vacuum leak causing unmetered air
- Low compression or mechanical issue in cylinder 6
02. Symptoms You Will Notice
- Check Engine Light on
- Rough idle or misfire
- Poor fuel economy
- Possible black smoke from exhaust
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Inspect fuel injector on cylinder 6 for leakage or sticking.
Step 3: Test oxygen sensor readings and compare bank 1 sensor 1 to bank 2 sensor 1.
Step 4: Perform a smoke test to check for vacuum leaks.
Step 5: Check compression on cylinder 6 and compare to other cylinders.
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 it can cause catalytic converter damage and poor performance. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Costs vary from $50 for a simple oxygen sensor replacement to $150 or more for injector or compression repairs.