Engine Controls - Idle Speed Too Low, Update ECM

Group 12
Engine Electrical

Bulletin Number
12 07 99

Woodcliff Lake, NJ
February 1999
Product Engineering

SUBJECT:
Increasing Idle Speed on ECM/DME (M5.2.1 or ME7.2)

MODEL:
E38 - 74OViLA with M62 engine produced as of 5197
E39 - 540iA with M62 engine produced as of 5/97

Situation:
Customer complains that the engine seems to stumble and the engine idle speed appears to be too low especially with the A/C off and when:

- Steering wheel is turned fully to the right or left

- Reverse gear is selected with automatic transmission

Cause:
Increased load requirement from steering/transmission

Correction:
In case of a customer complaint, the engine speed can be adjusted ±100 RPM by utilizing service function within DME diagnosis.

Procedure:
In order to increase the idle speed the following steps must be followed:

- No Faults stored in DME Fault Memory

- Engine must be at normal operating Temperature (at least 85°C)

- All electrical consumers must be switched oft

- Adaptation values should be cleared

Once the list conditions are met the idle speed can be increased by:

1. Select Digital Engine Management (displaying the DME diagnosis ID screen)

2. Select =>

3. Select "3 Service functions" then =>

4. Select "20 Idle speed adjustment" then =>

5. Current idle speed adjustments are displayed

6. Select =>

7. Menu of idle speed adjustment options is displayed.

8. Select an adjustment option from the menu and select =>

9. DIS will prompt you to perform certain operations, such as start engine.

10. After selecting => a screen displaying current engine speed and temperature will be displayed. At this point the engine speed can be increased or decreased in steps of 10 RPM. The total adjustment window is ±100 RPM.

11. Once the desired engine speed is obtained the new value must be stored. Once the new value is stored select the back arrow and the new idle speed adjustment setting will be displayed.

Warranty Information:
Information Only.