OBD-II code · Powertrain (generic, extended)

P231E Cylinder 11 Air-Fuel Ratio Imbalance Adjustment At Limit During Balance

The ECU continuously trims individual cylinders to equalise air-fuel ratio across the bank using ion-current or per-cylinder lambda feedback. For cylinder 11 the per-cylinder fuel correction has hit its software-side maximum or minimum without restoring balance, indicating the underlying mechanical or fuelling deviation is too large to compensate.

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.