29E1

What the Code Means

Code 29E1 belongs to the fuel injection system and is set by the engine control module (DME) when it detects a deviation in the air-fuel mixture in the second cylinder bank. It's the companion code to 29E0, which covers bank 1: the DME control logic is the same, only the bank where the mismatch is logged differs.

Under normal conditions the DME constantly trims the mixture based on oxygen sensor signals, holding it within a narrow tolerance. When the trims exceed the allowed limits, the module logs the fault and switches the mixture to emergency correction mode.

Symptoms

• Rough idle;
• Check Engine light on;
• fuel trims above 20%.

Diagnosis and Repair

1. Read the fault codes with ISTA or INPA.
2. Check the current fuel trims — values above 20% point to a significant mixture deviation.
3. Run an injector leak test: a leaking injector richens the mixture in the cylinders of its bank and explains the high trims.
4. Replace the leaking injectors.
5. Reset the DME adaptations after the repair and recheck the trims.

Secondary Problems

If you ignore the fault:

• Fuel dilution of the oil — leaking injectors keep delivering fuel into the cylinders and the crankcase;
• catalytic converter damage from prolonged operation with a shifted mixture;
• oxygen sensor failure from operating outside normal conditions.