INTERMITTENT/CURRENT ABS CODE 61 (REPLACE ABS PUMP RELAY). Buick LeSabre 1993

REVISION 05/27/93

THIS BULLETIN IS BEING REVISED TO ADD H CARS AND ADDITIONAL PROCEDURES.

REVISION 05/28/93

THIS BULLETIN IS BEING REVISED TO ADD THE WARRANTY STATEMENT.

REVISION 06/07/93

THIS BULLETIN IS BEING REVISED TO MAKE TEXT CHANGES IN STATEMENTS 4, 6, 7, 8, AND 10. ----------------------------------------------------------------------

SOME 1991-1993 DEVILLES AND FLEETWOODS AND 1991-1993 BUICK AND OLDSMOBILE C/H VEHICLES MAY EXPERIENCE AN INTERMITTENT ABS CODE 61.

THIS CONDITION MAY BE DUE TO A FAULTY ABS PUMP RELAY. DURING SELF TEST THE EBCM/EBTCM GROUNDS THE COIL SIDE OF THE PUMP RELAY AND IMMEDIATELY EXPECTS TO SEE GREATER THAN 500 MV AC FEEDBACK VOLTAGE FROM THE PUMP MOTOR RUN SENSOR WITHIN THE PRESSURE MODULATOR VALVE (PMV) ASSEMBLY. IF THE CONDITION IS INTERMITTENT, THE DIAGNOSIS IN THE SERVICE INFORMATION MANUAL, CHART F IN SECTION 5E1, WILL NOT DETECT THIS CONDITION BECAUSE THE PUMP MAY RUN DURING THE BLEED PROCEDURE WHICH MAY INCORRECTLY LEAD TO REPLACING THE EBCM/EBTCM.

TO DIAGNOSE AND REPAIR AN INTERMITTENT CODE 61 USE THE FOLLOWING PROCEDURE:

1. VISUALLY INSPECT AND ENSURE GOOD TERMINAL CONTACT OF THE LH MAXIFUSE 1 IN THE UNDERHOOD FUSE BLOCK, THE ABS MAIN RELAY, AND THE 4-WIRE PMV CONNECTOR C2.

2. WITH IGNITION OFF, DISCONNECT PMV CONNECTOR C2, MEASURE RESISTANCE FROM PIN E (HARNESS SIDE) TO THE BATTERY NEGATIVE TERMINAL.

O SHOULD BE LESS THAN 1 OHM. IF NOT, REPAIR HIGH RESISTANCE ON CIRCUIT 151 OR CLEAN G102.

3. MEASURE RESISTANCE FROM PIN D (PMV SIDE) TO F (PMV SIDE).

O SHOULD BE 10-40 OHMS. IF NOT, REPLACE PMV.

4. MEASURE RESISTANCE FROM PIN D (PMV SIDE) TO THE VALVE BLOCK CASE.

O SHOULD HAVE NO CONTINUITY. CONTINUITY PRESENT, REPLACE PMV.

5. DISCONNECT ABS PUMP RELAY, MEASURE RESISTANCE FROM PUMP RELAY CAVITY 4 (HARNESS SIDE) TO PMV CONNECTOR C2 PIN A.

O SHOULD BE 0.2 OHMS OR LESS. IF NOT, REPAIR OPEN OR HIGH RESISTANCE IN CIRCUIT 850.

6. WITH IGNITION ON, MEASURE VOLTAGE FROM PUMP RELAY CAVITY 4 (HARNESS SIDE) TO CHASSIS GROUND.

O SHOULD HAVE 0V. VOLTAGE PRESENT, REPAIR SHORT TO VOLTAGE ON CIRCUIT 850.

7. WITH IGNITION OFF, CONNECT PIN OUT BOX, MEASURE RESISTANCE FROM PIN 15 TO PIN 1.

O SHOULD HAVE NO CONTINUITY. CONTINUITY PRESENT, REPAIR SHORT TO GROUND ON CIRCUIT 854.

8. MEASURE RESISTANCE FROM PIN OUT BOX PIN 15 TO PUMP RELAY CAVITY 5 (HARNESS SIDE).

O SHOULD BE 0.2 OHMS OR LESS. IF NOT, REPAIR OPEN OR HIGH RESISTANCE IN CIRCUIT 854.

9. RECONNECT PMV CONNECTOR C2, MEASURE RESISTANCE FROM PIN OUT BOX PIN 31 TO 49.

O SHOULD BE 10-40 OHMS. IF NOT, REPAIR OPEN OR HIGH RESISTANCE IN CIRCUIT 1292 OR 1293.

10. MEASURE RESISTANCE FROM PIN OUT BOX PIN 31 TO 1, AND 49 TO 1.

O BOTH SHOULD HAVE NO CONTINUITY. CONTINUITY PRESENT, REPAIR SHORT TO GROUND ON CIRCUIT 1292 OR 1293.

11. IF ALL CHECK GOOD, REPLACE ABS PUMP RELAY, P/N 25553347.

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

FOR WARRANTY PURPOSES USE LABOR OPERATION H2475 AT .2 HOUR AND 0-.3 HOUR FOR ELECTRICAL DIAGNOSIS.

FIGURES: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.