What Does P02AF Mean?
The ECM has detected that the individual fuel trim correction for cylinder 6 has reached its minimum limit, meaning the system is removing as much fuel as possible from that cylinder but still detects an overly rich condition. Cylinder 6 is receiving more fuel than it should, and the ECM has exhausted its ability to compensate. The driver may notice rough idle, black exhaust smoke, poor fuel economy, and a fuel smell.
Common Causes
35%
Leaking cylinder 6 fuel injector allowing excess fuel into the combustion chamber when it should be closed
20%
Faulty injector driver circuit or ECM holding the cylinder 6 injector open longer than commanded
20%
Carbon buildup on the cylinder 6 intake valve (GDI engines) causing poor fuel atomization and incomplete combustion
15%
Low compression on cylinder 6 causing incomplete combustion and raw fuel passing into the exhaust
10%
Contaminated or degraded engine oil diluted with fuel affecting bank-level O2 sensor readings
Diagnostic Steps
1
Review live data for cylinder 6 individual fuel trim — confirm it is at or near the maximum negative correction limit (typically -25% to -30%) confirming the ECM is pulling maximum fuel.
2
Perform a relative compression test via cranking RPM analysis to verify cylinder 6 has adequate compression compared to other cylinders — a weak cylinder can appear rich due to poor combustion.
3
Remove and inspect the cylinder 6 spark plug for heavy black carbon fouling or wet fuel deposits confirming excess fuel entry.
4
With the fuel rail removed, apply regulated fuel pressure and observe the cylinder 6 injector tip for dripping — specification is typically no more than 1 drop per minute.
5
Check the cylinder 6 injector wiring for short circuits to ground or power, and verify injector resistance matches specifications (typically 11-17 ohms).
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The ECM has detected that the individual fuel trim correction for cylinder 6 has reached its minimum limit, meaning the system is removing as much fuel as possible from that cylinder but still detects an overly rich condition. Cylinder 6 is receiving more fuel than it should, and the ECM has exhaust...
The most common cause of P02AF (Cylinder 6 - Fuel Trim at Min Limit) is: Leaking cylinder 6 fuel injector allowing excess fuel into the combustion chamber when it should be closed
Typical repair costs for P02AF range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can be driven short distances but should be repaired promptly. Persistent rich operation on one cylinder washes oil from cylinder walls, accelerates catalytic converter degradation, and in severe cases poses a fire hazard from raw fuel in the exhaust.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02AF to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
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