Circuit Description
The electronic brake control module (EBCM) turns ON the Antilock Brake System (ABS) indicator by opening the ABS indicator control circuit. The ABS indicator is connected to the GAUGE fuse. This circuit has power when the ignition switch is in the ON or START positions. When the ignition switch is turned to the ON position, the EBCM turns ON the ABS indicator for 3 seconds for a bulb check. If the EBCM detects a malfunction, the ABS indicator will stay ON to warn the driver that the ABS is disabled and needs service.
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | The connector is off the EBCM. |
| • | An open or high resistance in the ABS indicator control circuit |
| • | An open, high resistance, or short in the ignition positive voltage circuit |
| • | An open or high resistance in the EBCM ground circuits |
| • | An internal EBCM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the ignition positive voltage circuit for an open or short to ground.
This step tests the EBCM ground circuits for an open or high resistance.
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An open in the ABS indicator control circuit will keep the ABS indicator ON.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 9 | Go to Step 3 |
3 | Measure the battery voltage. Is the battery voltage as specified? | Go to Step 4 | |
Did you find and correct the condition? | Go to Step 9 | Go to Step 5 | |
Test the ABS indicator control circuit for a open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | |
6 | Apply a ground to the ABS indicator control circuit. Is the ABS indicator ON? | Go to Step 7 | Go to Step 8 |
7 | Replace the instrument panel cluster assembly. Refer to Instrument Cluster Replacement . Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement . Is the repair complete? | Go to Step 9 | -- |
9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
