Cylinder 5 Fuel Trim at Min Limit
The P02AB code indicates that the engine control module (ECM) has detected the fuel trim for cylinder 5 is at its minimum limit, meaning the system is adding as little fuel as possible to correct a rich condition. This can be caused by a variety of issues including a stuck open fuel injector, a faulty oxygen sensor, a vacuum leak, or a mechanical problem such as low compression. The ECM continuously adjusts fuel delivery based on oxygen sensor readings; when it cannot lean out the mixture enough, it sets this code.
01. Most Common Causes
- Stuck open fuel injector on cylinder 5
- Faulty oxygen sensor (upstream)
- Vacuum leak
- Low compression on cylinder 5
- Fuel pressure regulator issue
02. Symptoms You Will Notice
- Check Engine Light on
- Rough idle or misfire
- Poor fuel economy
- Strong fuel smell 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 5 for leakage or sticking.
Step 3: Test oxygen sensor readings with a scan tool.
Step 4: Perform a smoke test to check for vacuum leaks.
Step 5: Check compression on cylinder 5.
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.
How much does it cost to fix?▼
Costs vary from $50 for a simple fix like a vacuum leak to $150 or more for injector replacement.