Brakes - Revised Diagnostic Procedures, ABS/TCS Code 74
Group Ref.: BrakesBulletin No.: 335018
Date: December, 1993
SERVICE MANUAL UPDATE
SUBJECT:
SECTION 5E - REVISED DIAGNOSTIC PROCEDURES FOR ABS/TCS DIAGNOSTIC TROUBLE CODE (DTC) 74
MODELS:
1992-93 BUICK PARK AVENUE/PARK AVENUE ULTRA
1992-93 BUICK LESABRE
1992-93 OLDSMOBILE NINETY EIGHT
1992-93 OLDSMOBILE EIGHTY EIGHT
1992-93 PONTIAC BONNEVILLE
This bulletin revises diagnostic procedures for ABS/TCS Diagnostic Trouble Code (DTC) 74 on the above listed vehicles equipped with TCS systems.
"Traction Off" indicator lamp is on and the traction control system disabled due to the presence of ABS/TCS Diagnostic Trouble Code (DTC) 74.
ABS/TCS DTC 74 can set due to the following conditions:
1. Faulty or misadjusted brake switch.
2. Short to ground in battery circuit to brake switch.
3. Faulty Pressure Modulator Valve (PMV) pressure switch.
4. Faulty PMV.
5. EBTCM detects short to ground or voltage at terminals 5, 8, 13, 26 or 32.
6. EBTCM detects an open in the pressure switch input, brakes applied input or return input circuits.
7. Poor terminal contact (PMV, EBTCM connectors).
8. Poor ground or loss of ground to EBTCM.
The DTC 74 diagnostic charts should be utilized after all proper System Checks and Visual Inspections have taken place per the applicable service manual diagnostic process. THE CHARTS PROVIDED MUST BE USED IN CONJUNCTION WITH THE APPLICABLE SERVICE MANUAL, SECTION 8A-44, OR BUICK ELECTRICAL SYSTEMS MANUAL (ABS SECTION) SCHEMATICS.