Fuel System - ASC Lamp ON, Fault Codes 40 or 50 Set
Group 34Brakes
Bulletin Number
34 01 00
Woodcliff Lake, NJ
September 2000
Service Engineering
SUBJECT:
ASC Light Illuminated, Fault Codes 40, 50
MODEL:
E34 (5 Series), E36 (3 Series) Vehicles with M50 or M52 engine
Situation:
The ASC light is illuminated and fault code 40 (E34), or fault code 50 (E36) are set in the ASC control module.
Diagnosis has found:
-- The setting of the secondary throttle assembly (ASC throttle valve) has no play and is not pretensioned.
-- Movement of the secondary throttle plate is smooth.
-- Voltage at the ASC throttle connector - pin 1 (battery volts), pin 2 (signal line - smooth voltage transition from closed throttle to open throttle), pin 3 (ground).
Cause:
Intermittent/high resistance contact at plug connectors.
Procedure:
1. Print the fault codes and attach a copy to the repair order
2. Disconnect the electrical connector at the throttle potentiometer and at the ASC control module. The ASC module is located behind the glovebox (E36), or in the E-box (E34). Clean the connectors with zero residue electrical contact cleaner, and apply Stabilant 22A Electrical Contact Enhancer. (For Stabilant 22A application instructions and availability, refer to SIB 61 05 00.)
3. Reinstall the connectors.
Warranty Information:
Covered under the terms of the BMW New Vehicle Limited Warranty.