Engine Controls - Various Driveability Conditions
SI B12 15 08Engine Electrical Systems
August 2008
Technical Service
Similar information may be found in SI B24 05 08 dated August 2008.
SUBJECT
E65, E66 with N62TU - Various Driveability Complaints
MODEL
E65, E66 (750i, 750iL) produced from 03/05 up to 09/07
SITUATION
The customer complains about one or a combination of the following situations, listed below:
1. The engine has a rough idle, or the idle fluctuates on the initial cold start when the outside temperature exceeds 59F.
2. Creep speed bucking.
3. Drivetrain "clunks jerks" when reaccelerating at low speed ("load reversal").
4. The vehicle jerks when accelerating from a stop ("throttle calibration too aggressive"), or the vehicle does not accelerate smoothly from a stop ("brief delay and then lurches forward").
5. Shudder and/or noise and/or surge and/or hesitation from the transmission during a cold start operation.
6. Harsh 2-1, 3-2 downshifts when coming to a stop ("harsh jolt/bang felt while slowing down").
7. Harsh jolt felt when reaching the top of a hill, driving uphill ("felt like a harsh 1-2 up-shift").
The driveability complaints are intermittent and they are not easily reproducible in the workshop. No fault codes are stored in the DME or EGS control modules. Countermeasures from SI B12 27 05 ("N62TU Engine pinging & idle fluctuation") were performed without success.
CAUSE
Combination of the DME and EGS software
CORRECTION
On a customer complaint basis only, and when the problem description matches one of those listed above, contact DME TeileClearing via the PuMA case titled "750 Driveability Retrofit".
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