Brakes - Revised Diagnostic Procedures Code 45
Group Ref.: BrakesBulletin No.: 335015
Date: November, 1993
SERVICE MANUAL UPDATE
SUBJECT:
SECTION 5E - REVISED DIAGNOSTIC PROCEDURES FOR ABS OR ABS/TCS DIAGNOSTIC TROUBLE CODE 45
MODELS:
1991-94 BUICK LESABRE, PARK AVENUE/PARK AVENUE ULTRA
1991-93 CADILLAC DEVILLE, FLEETWOOD AND SIXTY SPECIAL
1991-94 OLDSMOBILE NINETY EIGHT, EIGHTY-EIGHT
1991-94 PONTIAC BONNEVILLE
This bulletin revises diagnostic procedures for ABS or, if equipped, ABS/TCS Diagnostic Trouble Code (DTC) 45 on the above listed vehicles equipped with ABS or ABS/TCS systems.
"ABS" and, if equipped, "Traction Off" indicator lamps are on and both systems disabled due to the presence of ABS or ABS/TCS Diagnostic Trouble Code (DTC) 45.
ABS or ABS/TCS DTC 45 can set due to the following conditions:
1. Open or short to ground in the left front inlet valve circuit.
2. No battery voltage detected at the Pressure Modulator Valve (PMV) when the ignition switch is in the "run" position.
3. No battery voltage detected at the EBCM/EBTCM terminals 33, 35 (Traction Control only), 3, 53 or 20.
4. Main relay fails open.
5. Open in main relay control circuit.
6. High resistance in any PMV inlet/outlet valve circuit.
7. If equipped with Traction Control, high resistance in any isolation valve circuit.
8. Poor terminal contact (PMV, EBCM/EBTCM or main relay connectors).
9. Poor ground or loss of ground to EBCM/EBTCM.
In addition, DTC 45 may also set interminently due to low system voltage (extended cranking, low battery but vehicle eventually starts, etc.).
The DTC 45 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.
The vehicle should be in "park" and allowed to idle with the hood down for at least twenty minutes before proceeding with the diagnostic charts.
Diagnostic Trouble Code 45 Charts