Table B ABS Warning Indicator Inoperative

Table B: ABS Warning Indicator Inoperative (Part 1 Of 2):

Table B: ABS Warning Indicator Inoperative (Part 2 Of 2):

Table B Schematic:

Circuit Description
The Electronic Brake Control Module (EBCM) controls the operation of the amber ABS indicator lamp by means of a lamp driver relay.
The amber ABS indicator lamp is connected to the GAUGE fuse through CKT 839. This circuit is hot in ON and START ignition switch positions.

When the lamp driver relay is in the OFF state (CKT 9U01 is open), the lamp driver relay grounds the amber ABS indicator lamp through CKT 875.
This causes to turn ON the amber ABS indicator lamp.

When the EBCM commands OFF the ABS indicator, the EBCM turns ON the lamp driver relay by grounding CKT 852A/B. This causes the lamp driver relay to open the path to ground in CKT 875, turning OFF the amber ABS indicator lamp.

When the ignition switch is turned to the ON position, the EBCM turns ON the ABS indicator for 3 seconds for a bulb check. Whenever a malfunction is detected within the ABS system, the EBCM turns ON the ABS indicator, notifying the driver that ABS needs to be serviced. If the EBCM commands the red BRAKE warning indicator ON due to an ABS malfunction that may degrade base braking operation and cannot do so, the ABS indicator will flash to indicate the serious nature of the problem.

Diagnostic Aids
The following list contains items that need to be inspected when diagnosing this system:
^ Open GAUGE fuse.
^ Open bulb filament.
^ Open or poor G200.
^ Short to ground in lamp driver relay control circuit (CKT 825A/B).
^ Open within I/P gage printed circuit.
^ Faulty lamp driver relay (open contacts).
^ Faulty EBCM.
Inspect the following harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness before component replacement:
^ Lamp driver Module.
^ EBCM connector C1.
^ I/P cluster C3.


Test Description
The numbers below refer to step numbers on the diagnostic table.
3. Checks the amber ABS indicator lamp.
5. Checks the amber ABS indicator lamp.
6. Checks for power to the I/P gage cluster.
7. Checks ground circuit.
8. Checks for a short to ground in the lamp driver module control circuit causing the relay to stay ON even though the EBCM is commanding it OFF.
9. Checks for continuity at the lamp driver module in the OFF state.
18. Checks EBCM operation of the ABS indicator through Tech 2 scan tool commands.