Engine Controls - Rough Idle/Misfire/Loss Of Power

SI B13 05 08
Fuel Systems

May 2009
Technical Service

This Service Information bulletin supersedes SI B13 05 08 dated February 2009.

[NEW] designates changes to this revision

SUBJECT
Rough Idle, Rough Running, Misfiring and Loss of Power

MODEL
E90, E92 and E93 M3 with S65 engine

[NEW] SITUATION
Scenario 1:

The customer complains that a loss of power occurs when idling; the Service Engine Soon lamp is illuminated; and fault code 2B23 (Idle-air actuator, regulator monitoring) is stored in the DME fault memory. This complaint can be intermittent.

Scenario 2:

The customer complains that the vehicle runs rough while idling or driving; the vehicle will misfire; and a loss of power can occur. The vehicle's Service Engine Soon lamp is illuminated and fault code 2B23 (Idle-air actuator, regulator monitoring) will be stored in the DME fault memory. The vehicle's engine control may enter the emergency program, and various misfire faults are stored. This complaint can normally be reproduced in the workshop very easily.

[NEW] CAUSE
Scenario 1:

Defective idle actuator

Scenario 2:

The idle circuit has become blocked or restricted, due to an internal separation of the rubber hose located between the idle-air actuator and the intake manifold. The layers of the rubber hose will tear away and restrict one of the idle strips located on each engine bank. This restriction will lead to a misfire and rough running while idling or driving. In some cases, the engines oil consumption can increase.

[NEW] PROCEDURE
Scenario 1:
Replace the Idle Control Valve

Scenario 2:
Remove the intake manifold in accordance with RA 11 61 050, Removing and installing air intake manifold (S65), to inspect all idle circuit components.





Remove and inspect the hose (1) located between the idle-air actuator and intake manifold. Remove and inspect the idle-air actuator (2). If debris is found, remove the debris, but do not replace the idle-air actuator. Remove and inspect both idle strips. If debris is found inside the idle strips, both idle strips must be replaced. Whenever rubber hose debris is found in the idle circuit, it will be necessary to replace the rubber hose (1) between the idle-air actuator and the intake manifold as well. The rubber hose (4) located between the idle strips should be inspected and cleaned; do not replace this item.





[NEW] PARTS INFORMATION








[NEW] WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty or the Certified Pre-Owned Program for scenario 1 only.





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