P02A7
Cylinder 4 - Fuel Trim at Min Limit
Fuel & air metering
Generic OBD-II
High
What it means
P02A7 means the per-cylinder fuel trim for cylinder 4 has reached its minimum (lowest) limit — the ECM has pulled back as much fuel as it can for that cylinder and still sees it running rich. It typically points to an injector delivering too much fuel or high fuel pressure. The engine still runs, but the maxed-out correction should be diagnosed before it fouls the plug or converter.
High
Can I keep driving? Usually drivable — the engine runs, but cylinder 4 is trending rich at the correction limit, which can foul the plug and stress the catalytic converter over time.
Common symptoms
What you'll notice
- Check-engine light on
- Rough or uneven idle
- Possible cylinder 4 misfire or hesitation
- Fuel smell or reduced fuel economy
Common causes
Most likely first
- Leaking or over-delivering cylinder 4 fuel injectorLikely
- Excessive fuel pressure adding fuel to cylinder 4Common
- Cylinder-specific compression or contribution imbalanceCommon
- Faulty engine control module (ECM) — least commonLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and compare cylinder 4's fuel trim to the other cylinders.
- Inspect the cylinder 4 injector for leakage and check overall fuel pressure against spec.
- Perform an injector balance/leak-down test on cylinder 4; check the spark plug for fouling.
- Replace the injector if it is over-delivering; verify compression if trims stay pinned. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P02A7?+
Short term yes, but the ECM has run out of room to correct cylinder 4's mixture. Continued rich running can foul the plug and harm the converter, so fix it soon.
Can I just clear P02A7?+
It clears, but the trim will hit its limit again until the underlying fuel or injector issue on cylinder 4 is fixed.
Related codes
Often seen with P02A7
Read & clear P02A7 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX