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.
• | 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. |
• | In order for the ABS indicator to come On, there must be battery voltage at terminal B of the Brake Lamp Driver Module and a good ground at terminal D of the Brake Lamp Driver Module. |
• | If the ABS indicator does not come On and there are no DTCs, then the cause may be one of the following: |
• | A malfunctioning Brake Lamp Driver Module |
• | CKT 875 is open |
• | No power or ground for the Brake Lamp Driver Module |
• | A malfunctioning IPC |
• | A damaged ABS indicator bulb |
• | The EBCM/EBTM sets a DTC when CKT 852 is open, shorted to ground, or shorted to voltage |
• | More than one indicator bulb will be inoperative if the battery feed to the IPC indicators is open |
The number(s) below refer to the step number(s) on the diagnostic table.
This step checks if the EBCM/EBTCM is not capable of removing the ground for CKT 852
This step checks for a short to ground in CKT 39.
This step checks for voltage at brake lamp driver module.
This step checks for voltage from IPC.
This step checks if brake lamp driver module has a good ground.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
Does the ABS indicator turn on? | -- | |||
3 |
Is the fuse OK? | -- | ||
4 |
Is the voltage within the specified range? | Battery Voltage | Go to Wiring Repairs in Wiring Systems | |
Is the resistance equal to the specified value? | OL (infinite) | |||
Is the voltage within the specified range? | Battery Voltage | |||
Using J 39200 DMM, measure the voltage from terminal E of the brake lamp driver module harness connector to a good ground. Is the voltage within the specified range? | Battery Voltage | |||
8 | Repair CKT 39 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
9 |
Is the fuse OK? | -- | Go to Diagnostic System Check | |
Is the resistance less than the specified value? | 2 ohms | |||
11 |
Is the resistance less than the specified value? | 2 ohms | ||
12 | Replace the brake lamp driver module. Refer to Lamp Driver Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
13 | Repair CKT 1250 for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
14 | Suspect the IPC. Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console. Is the diagnosis complete? | -- | Go to Diagnostic System Check | -- |
15 | Repair an open or high resistance in CKT 875. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
16 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
17 | Repair an open or high resistance in CKT 39. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |