Circuit Description
The instrument cluster controls the operation of the ANTILOCK indicator. The EBTCM reports the desired status of the ANTILOCK indicator via serial data class 2 messages. The hard wired circuit is a back-up reporting circuit. The EBTCM supplies ground through the circuit when the ABS is operating properly. Using the serial data messages and back-up circuit, the instrument cluster decides whether to turn on the ANTILOCK indicator.
Conditions for Setting the DTC
All of the following conditions occur:
| • | The EBTCM commands the ANTILOCK indicator ON. |
| • | The EBTCM detects one of the following conditions in the ANTILOCK indicator control circuit: |
| - | An open |
| - | A short to ground |
| - | A short to voltage |
Actions Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The ABS remains functional. |
| • | For a short, the ABS indicator remains OFF. |
| • | For an open, the ABS indicator is turned ON. |
Conditions for Clearing the DTC
| • | The condition for DTC is no longer present and you used scan tool Clear DTCs function. |
| • | The condition for DTC is no longer present and you used the On-Board Clear DTCs function. |
| • | The EBTCM does not detect the DTC in 50 drive cycles. |
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
Test Description
The numbers below refer to step numbers on the diagnostic table.
-
This step checks if the instrument cluster has the ability to operate the ABS indicator.
-
This step checks for a short to ground in CKT 852.
-
This step checks for a short to voltage in CKT 852.
-
This step checks for an open in CKT 852.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Are codes U1300 or U1301 present? | -- | Go to DTC U1300 Class 2 Short to Ground or DTC U1301 Class 2 Short to Battery in Data Link Communications | Go to Step 3 |
Did the ABS indicator turn ON then OFF? | -- | Go to Step 4 | Go to Step 10 | |
Is the resistance within the specified range? | OL (Infinite) | Go to Step 6 | Go to Step 5 | |
5 | Repair the short to ground in CKT 852. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
Is the voltage greater than the specified value? | 1 V | Go to Step 8 | Go to Step 7 | |
Is the resistance less than the specified value? | 5 ohms | Go to Step 11 | Go to Step 9 | |
8 | Repair the short to voltage in CKT 852. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
9 | Repair the open in CKT 852. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
10 | Inspect the instrument cluster. Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console. Did you complete the diagnosis? | -- | -- | |
11 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | -- |
