For 1990-2009 cars
ABS Components
Cell 44: Buick Indicators
Cell 44: Pontiac Indicators
Cell 44: Oldsmobile Indicators
Cell 10: IGN SW Fuse (1 of 2)
Cell 10: PCM Fuse
Cell 14: G202
Handling ESD Sensitive Parts Notice

### Circuit Description

The ABS Indicator driver circuit runs from the Instrument Panel Cluster (IPC) through the brake lamp driver module to the EBCM/EBTCM. The IPC supplies voltage to the ABS indicator. The EBCM/EBTCM controls the ABS indicator through the brake lamp driver module. The brake lamp driver module acts as an inventor. When the EBCM/EBTCM supplies a ground for the brake lamp driver module the ABS indicator remains Off. When the EBCM/EBTCM removes the ground for the brake lamp driver module the ABS indicator turns On by using the ground at the brake lamp driver module terminal D.

### Diagnostic Aids

• | Perform a thorough inspection of the wiring and connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

• | If the indicator lamp is On, the battery voltage to terminal B and the ground at terminal D at the brake lamp driver module are OK.

• | If the indicator remains On and there are no DTCs, then the cause is either CKT 875 shorted to ground, a malfunctioning brake lamp driver module, or a malfunctioning EBCM/EBTCM.

• | If CKT 852 is open, shorted to ground, or shorted to voltage, the EBCM/EBTCM will set a DTC.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks to see if the EBCM/EBTCM is not cable of supplying the ground.

2. This step checks to see if CKT 875 is shorted to ground.

#### ABS Indicator On with No DTC Set

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check
2 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the EBCM/EBTCM connector.
3. Connect the J 39700 universal pinout box using the J 39700-25 cable adapter to the EBCM/EBTCM harness connector only.
4. Connect a fused jumper between terminal 13 and ground terminal B of the J 39700 .
5. Turn the ignition switch to the RUN position. Do not start the engine.

Does the ABS indicator turn off?

--

Go to Step 3

Go to Step 4

3 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | --
4 |

1. Turn the ignition switch to the OFF position.
2. Remove the fused jumper.
3. Disconnect the brake lamp driver module.
4. Turn the ignition switch to the RUN position. Do not start the engine.

Is the ABS indicator on?

--

Go to Step 5

Go to Step 6

5 | Repair CKT 875 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | --
6 | Replace the brake lamp driver module. Refer to Lamp Driver Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | --