Engine Controls - MIL ON/Multiple fault Codes Set
SI B12 05 06Engine Electrical Systems
May 2006
Technical Service
SUBJECT
N62TU - Diagnosis of Mixture Adaptation Faults
MODEL
E65/E66 with N62TU from 03/05
SITUATION
The "Service Engine Soon" light is illuminated and multiple adaptation faults (e.g. 29E8, 29F0, 29EE, 29E7, 29EF, 29ED, 2D32) are stored in the DME. DIS/GT1 status request indicates the multiplicative and additive values running in opposite directions (e.g. lean multiplicative and rich additive, or the opposite, depending on the root cause).
Customer may also complain of engine rough idle.
CAUSE
Restriction or leakage in the un-metered airflow (before AMM) leading to incorrect air mass meter readings
In most cases, the airflow disturbance was caused by incorrect reinstallation of the air intake components, previously removed for unrelated repairs (e.g. headlight replacement, body work, etc.
1. Two halves of the air-box incorrectly reassembled after e.g. headlight repair (locating tab not inserted into a locking slot).
2. Example of the correctly installed air-box.
3. The cutout for the air intake in the front left panel is missing which blocks the airflow on that side. This situation was caused by installation on of an incorrect component (front panel from N62 engine) after body repair.
The picture shows the panel with the correct cut out.
4. The air turbulence diffuser (connecting front panel cutout to the air-box) is missing after unrelated body repair.
WARRANTY INFORMATION
Work time and parts incurred to correct previously insufficient repairs are not covered by the BMW New Vehicle Limited Warranty.
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