Circuit Description
The valve relay is part of the electronic brake control module (EBCM). The EBCM turns ON the valve relay when the ignition switch is in the ON position and no malfunction exists in the ABS. The valve relay provides power to the antilock brake system (ABS) solenoid valves.
Conditions for Running the DTC
DTC 63 can be set anytime the ignition switch is in the ON position.
Conditions for Setting the DTC
The EBCM detects one of the following:
| • | valve relay voltage is low. |
| • | valve relay voltage is 12 V when the EBCM is not requesting it to be. |
| • | an open or short in the valve solenoid circuitry. |
Action Taken When the DTC Sets
| • | The ABS and traction control system are disabled. |
| • | The ABS and TRAC OFF warning indicators turn ON. |
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
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:
| • | An open, high resistance or short to ground in the EBCM battery positive voltage circuit |
| • | An open, high resistance or short to ground in the EBCM 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 in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.
-
This step tests the EBCM ground circuits.
-
This step tests the EBCM battery positive voltage circuits.
-
This step tests the EBCM ignition positive voltage circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform A Diagnostic System Check - ABS? | -- | Go to Step 2 | |
2 |
Does the solenoid valve function properly? | -- | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the voltage for both circuits measure as specified? | Approximately 12 V | Go to Step 4 | Go to Step 6 |
4 |
Does the voltage measure as specified? | Approximately 12 V | Go to Step 5 | Go to Step 7 |
Test the EBCM ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 | |
Test the battery positive voltage circuits for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 | |
Test the ignition positive voltage circuits for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 | |
8 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
9 | Replace the Brake Pressure Modulator Valve (BPMV). Refer to Brake Pressure Modulator Valve Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
