ABS & TC/ABS System - Diode Locator and Fault Diagnosis: Overview

CATEGORY
Brakes

SECTION
5

PAGE
6

ISSUE
06/93-0346

CODE
500

Subject:
Diodes for ABS and TC/ABS Systems


Application:
900 and 9000 Models

Supersedes 02/92-0184

This Service Bulletin is being reissued to update the information to include 1993 models.





It may sometimes be difficult to diagnose and locate a failed diode in either the ABS or TC/ABS system. This TSB describes the most common fault symptoms as well as suitable methods of fault diagnosis and diode replacement, Figure 1.

Cars Affected:

900 and 9000 Models as specified below in "Fault Diagnosis".

Parts:

Diode P/N 44 24 172
This diode is of B4 252 GP G1 type.

Special Tools:

Breakout Box P/N 86 11 006
35-pin LH Cable P/N 86 11 154
55-pin TC/ABS Cable P/N 86 11 030
Multimeter, with diode or resistance measurement.

Use the wiring diagram in Service Manual 3:2 for the relevant system when testing the circuits.