Engine Controls - Power Drop at 4,000 RPM

Service Measure

B12 209 05

04/06/2005

Engine Electrical

Subject
M54B30 MS45.1; Engine Power Drops at 4000 rpm

Vehicle
E46, E60 with M54B30 and manual transmission.

Complaint
Customer may complain of an engine power drop at approximately 4000 rpm during aggressive acceleration.

Cause
Ignition timing retardation due to unfavorable tolerances of DISA valve flap shaft.

Vibrations of a DISA valve are interpreted by the knock sensor system as a detonation combustion.

Measure
On a customer complaint basis, replace DISA valve with the improved part (PN 11 61 7 544 805).

After DISA replacement, connect vehicle to DIS/GT1 and from DME identification page retrieve the programmed and basic DME part numbers.

Reprogram DME with the latest available DIS CDI SSS CIP software version. DME programming should last for at least 20 minutes and should result in both programmed and basic control unit number changes.

Reprogramming of DME clears the long-term knock sensors adaptations. If the knock adaptation values are not cleared, the vehicle will still exhibit the power lack complaint, even with the improved DISA valve installed.

Important:
In the event the DME programming takes only a short period of time (approximately 5 minutes), and the basic control unit part number has not been changed, the adaptation clearing process has not been accomplished.
In such a case, contact Technical Hotline - Drivetrain via a PuMA case, requesting authorization for DME shipment to Engineering Department for reprogramming. For the PuMA case title use the following: "MS45.1 DME KNOCK ADAPTATION RESET".