What Does P02C6 Mean?
The ECM has detected that the individual fuel trim correction for cylinder 12 has reached its maximum enrichment limit. The PCM is adding as much extra fuel as it can to cylinder 12 but cannot achieve the target air/fuel ratio, indicating a persistent lean condition isolated to that cylinder. The driver may notice rough running, reduced power, or misfires especially under load in high-cylinder-count engines (V12 or W12).
Common Causes
35%
Restricted or partially clogged fuel injector on cylinder 12 reducing fuel delivery
25%
Intake manifold vacuum leak at cylinder 12 runner causing unmeasured air entry
20%
Low fuel pressure or weak fuel pump not supporting all 12 cylinders adequately
12%
Faulty injector driver circuit or wiring harness issue to cylinder 12
8%
Compression loss on cylinder 12 causing incomplete combustion
Diagnostic Steps
1
Monitor cylinder 12 individual fuel trim via live data — values near +25% or higher confirm the ECM is at its maximum enrichment correction limit.
2
Perform a fuel injector balance test or relative compression test via scan data to compare cylinder 12 contribution against other cylinders.
3
Check fuel pressure with a mechanical gauge at the fuel rail — confirm it meets manufacturer specification (typically 55-62 PSI for DI systems) under both idle and load conditions.
4
Inspect the wiring harness and connector at the cylinder 12 injector for corrosion, damaged pins, or chafing — measure injector resistance (typically 11-18 ohms for high-impedance injectors).
5
Perform a cylinder leakdown test on cylinder 12 — less than 10% leakage is acceptable; listen at intake, exhaust, and crankcase for leak source identification.
Estimated Repair Cost
$200 - $950
Parts + labor, varies by vehicle and location
The ECM has detected that the individual fuel trim correction for cylinder 12 has reached its maximum enrichment limit. The PCM is adding as much extra fuel as it can to cylinder 12 but cannot achieve the target air/fuel ratio, indicating a persistent lean condition isolated to that cylinder. The dr...
The most common cause of P02C6 (Cylinder 12 - Fuel Trim at Max Limit) is: Restricted or partially clogged fuel injector on cylinder 12 reducing fuel delivery
Typical repair costs for P02C6 range from $200 to $950, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Drivable in the short term, but continued operation risks catalytic converter damage from the lean/rich cycling on cylinder 12. Extended driving may cause elevated emissions and potential cylinder damage. Have it diagnosed within a few days.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02C6 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
