Engine Controls - Repeated Juddering Or Surging On Accel.

SI B11 10 12
Engine

January 2013
Technical service

SUBJECT
N20 Engine: Repeated Juddering or Surging While Accelerating

MODEL
E84
E89
F10
F25
F30

SITUATION
The vehicle judders or surges repeatedly while accelerating in hot ambient temperatures between 3,000 RPM and 5,000 RPM. The Service Engine Soon lamp is not illuminated, and no fault codes are stored in the vehicle memory related to this complaint.

CAUSE
The EPDW (electropneumatic pressure convertor) for the turbocharger wastegate valve is binding internally.

PROCEDURE
When no fault codes related to this complaint are stored in the vehicles memory:





1. Remove the engine acoustic cover as per Repair Instruction 11 12 090, "Removing and installing/renewing acoustic cover (N20)."

2. Locate the EPDW located near the engine oil fill cap.

3. On the side the EPDW, there is a series of numbers printed.

Do not remove the EPDW.





The date code located on the side of the EPDW needs to be 12T158 or greater.

If the date code is 12T157 or lower, the EPDW will need to be replaced.

Refer to the illustration.





4. Remove the electrical connector (1).

5. Remove the screws (2).

6. Remove vacuum lines marked "OUT" and "VAC."

7. Remove EPDW.

8. Install the new EPDW, connectors and vacuum lines. Install and torque the attaching screws to 3 Nm (2).

Note:
When the ISTA system message displays: Battery voltage only "XX.XX" V. Please connect charger. Please note the displayed battery voltage reading in the repair order comments section. This documentation is not necessary when part of an approved Technical Service repair procedure; the battery charger is required to be attached before performing the Vehicle Test.





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