SRS - Diagnostic Cables

Group 72
Equipment and
Accessories

Bulletin Number
72 02 91 (3338)

Woodcliff Lake, NJ
December 1994
Product Engineering

This Service Information bulletin supersedes orange S.I. 72 02 91 (3338) dated August 1991, which should be removed from your S.I. binder and discarded. Changes are shown with asterisks.

SUBJECT:
SRS Diagnostics

MODELS:
E30 and E24 (equipped with Siemens SRS Control Module)

Situation:
The BMW Service Tester can be used to call up fault codes via the RxD and TxD lines on the control module. This will provide a convenient and reliable method for testing and diagnosis, as well as eliminate any confusion as to the interpretation of flash codes.

As the vehicle wiring harness was not equipped with TxD and RxD leads connecting the SRS control module and the Diagnostic Connector, the special tool/procedure below must be followed in order to connect diagnostic equipment to the SRS control module on the affected vehicles. This procedure allows fault codes to be recalled/cancelled.

Procedure:
**Using the special cable connector (SD # 91-020)**, connect the Service Tester Diagnostic cable to the SRS control module side of C250 (E24), C280 ('92 E30 Convertible), or C240 (E30) as appropriate. Note that jumper leads contained in the BMW Connector Test Kit (P/N 88 88 6 900 322) can be used if the SD # 91-020 adapter is not available. [Each Dealer was sent one adapter. Refer to S.I. 04 29 91 (3446).] Use the chart below and the illustration in this bulletin as a guide to the connections.

Diagnostic Cable SRS Connector

E24 Pin # 15 (RxD) C250 Pin # 6 (WT/YL)
Pin # 20 (TxD) C250 Pin # 2 (WT/VI)
Pin # 19 (Ground) Good Vehicle Ground

**E30 '92 Pin # 15 (RxD) C280 Pin # 6 (WT/BK)
Convertible Pin # 20 (TxD) C280 Pin # 7 (WT/VI)
Pin # 19 (Ground) Good Vehicle Ground

E30 Pin # 15 (TxD) C240 Pin # 6 (WT/YL)
Pin # 20 (TxD) C240 Pin # 2 (WT/VI)
Pin # 19 (Ground) Good Vehicle Ground**

Once the proper connections are made, the control module can be eyed using the Service Tester. **The new DIS Tester does not support this procedure at this time.**




Illustration shows connections between Diagnostic Cable on BMW Service Tester and SRS control module in vehicle. Refer to chart for detailed description of connector Pin numbers.