ABS Light - Stays Illuminated at All Times
Group Ref.: BrakesBulletin No.: 465001
Date: March, 1994
SUBJECT:
ABS BRAKE LIGHT ILLUMINATED, NO RED BRAKE LIGHT ON AND NO CODES OR SERIAL DATA RETRIEVED FROM THE TECH-1 OR CAMS. (REPAIR POWER OR GROUND AT THE 10 PIN CONNECTOR OR REPLACE BPMV MODULE "CAP" AND RELOCATE G124 GROUND CONNECTION)
MODELS:
1993-94 CHEVROLET AND GMC TRUCK G VANS WITH YF7 ONLY (CONVERSION VANS)
CONDITION:
Some owners have commented that the yellow ABS light stays illuminated at all times.
CAUSE:
There are 3 conditions which may contribute to the above condition. They are:
1. Insufficient supply of power or ground on the 10 pin connector going into the BPMV. Power is received through terminal A of the 10 pin connector when the ignition switch is turned to the on position. Ground is received on the 10 pin connector through terminal J at all times. Any intermittent or change in resistance on either of these wires will cause the ABS module "CAP" (located in the BPMV) to malfunction. Technicians should carefully check for changing or high resistance through terminal A or J.
2. A capacitor C35 mounted to the printed circuit board of the BPMV may become a direct current path to ground, causing damage to the component and the printed circuit board. If this occurs, the BPMV module "CAP" will become disabled.
3. The BPMV and PCM, and Body ground share the same location on the back of the right hand cylinder head. The body ground strap "G124" should be moved away from this location to prevent future module problems.
CORRECTION:
Replace the BPMV Control Module assembly "CAP" and relocate the body ground G124 to a new location.
It will be necessary to properly diagnose this condition by following the procedures located in the diagnostics and service procedures provided below.
Once you have achieved the proper definition of the above condition, it is mandatory that you contact K-TAC 1(800) 546-4227 for further information.
DIAGNOSTICS PROCEDURE:
1. Connect TECH-1 or CAMS to the DLC. If a DTC code is captured, refer to the Service Manual for proper repairs. If no DTC codes or serial data is not captured, continue diagnostics.
2. Remove TECH-1 or CAMS. Using a DVM (Digital Volt Meter) or equivalent, "not a light meter", measure voltage at the DLC diagnostics connector pin "A" to pin "H". If voltage registers below 5 volts, record this voltage on the repair order for further reference.
3. Disconnect the 10 pin connector from the BPMV. Using a DVM (Digital Volt Meter) or equivalent, "not a light meter", measure voltage at pin "A" to pin "J". This procedure is to identify the ignition feed signal. Record voltage on the repair order for further reference.
4. It will be necessary to properly diagnose this condition by following the procedures located in the diagnostics and service section provided. Once you have achieved the proper definition of the above condition, it is mandatory that you contact K-TAC at 1-800-546-4227 for further information.
SERVICE PROCEDURE:
The service procedure will be included in the parts kit.
FLINT ASSEMBLY VIN BREAKPOINTS:
(From SOP 1993 to the following VIN Breakpoints 1994)
CHEVROLET: RF120591
GMC: RF507903
SERVICE PARTS INFORMATION
The BPMV module "CAP" must be ordered through K-TAC. The kit assembly P/N is 12891300.
All replaced BPMV modules "CAPS" must be returned to Kelsey-Hayes for analysis.
WARRANTY INFORMATION
For vehicles repaired under warranty, use: