A/T - Erroneous Fault Code 40, Pressure Regulator

Group 24
Automatic Transmission

Bulletin Number
24 06 94

Woodcliff, NJ
November 1996
Product Engineering

This Service Information bulletin supersedes S.I. 24 06 94 (4134) dated May 1995 which should be removed and discarded from your S.I. binder.

The black bar and double asterisks identifies changes made to this revision.

SUBJECT:
Transmission Control Module Fault Code 40

MODEL:
E34, E36 with A4S 310R/ 270R Automatic Transmission

Situation:
"Trans Program" is displayed in the matrix (E34) or the transmission fault indicator is illuminated (E36). Cycling of the ignition switch restores normal operation. Fault code 40 - Pressure Regulator, is stored in the fault memory of the transmission control module. The setting of Fault Code 40 occurs very intermittently and may not be "currently present" at the time the vehicle is being diagnosed.

Cause:
The pressure regulator monitoring circuitry of the control module is too sensitive and may cause Fault Code 40 to be set erroneously.

Correction:
The pressure threshold values in the latest EPROMs have been changed to eliminate the erroneous setting of fault code 40. The EGS control module EPROM is to be replaced if it is determined that FC 40 has been set erroneously.

Procedure:
Prior to the replacement of any components perform the following:

^ Check fault memory of EGS for existence of fault code 40.





^ If fault code 40 is "currently present" in the EGS control module and confirmed to be non intermittent, (i.e. cycling of the ignition switch does not change fault status) check the resistance between the following pins with the ignition switched off and the control module not connected:

**^ If fault code 40 is not "currently present" replace the EPROM in the transmission control module. Please refer to S.I. 24 05 95 (4294) for complete instructions on exchanging the transmission control module EPROM.**





^ The replaced EPROM can be identified by a new Software Number being displayed on the EGS identification screen of the service tester:

** NOTE:
THE EPROMs LISTED ABOVE PERTAIN TO VEHICLES EQUIPPED WITH SHIFT LOCK. Vehicles produced prior to 9/91 may not be equipped with a shift lock solenoid. If the vehicle does not have shift-lock (the range selector switch can be removed from park or neutral without depressing the brake pedal) please contact the Technical Service Hotline in order to obtain a replacement Service EPROM.**





Parts Information:
The updated transmission control module EPROM can be ordered by the part numbers based on model and production range:

**Note:
The BMW hardware numbers listed above may not be all inclusive. If the BMW hardware number of the installed EGS module is not listed above and the vehicle is equipped with shift-lock, install the EPROM that matches with the model and production period of the vehicle.**

Description Pressure Regulator

Part Number 24 35 1 421 602





Warranty Information:
Parts and labor will be reimbursable under the terms of the applicable BMW New Car Limited Warranty.