Circuit Description
The EBCM microprocessor grounds the isolation coil to energize and close the isolation valve. This will prevent any additional brake pressure applied by the driver from reaching the wheel. Further increases in brake pressure will be prohibited. Each isolation valve is closed independently to isolate each wheel.
Conditions for Setting the DTC
Isolation time (pressure hold) exceeds 120 seconds.
Action Taken When the DTC Sets
| • | The ABS indicator lamp turns on |
| • | The ABS disables |
DTCs C0269 and C0274 are ignition latched DTCs, which indicates that the above actions remain true until the ignition switch is turned to OFF (even if the cause of the DTC is intermittent).
Conditions for Clearing the DTC
| • | Repair the conditions responsible for setting the DTC |
| • | Use the Scan Tool Clear DTCs function |
Diagnostic Aids
Repair any other DTCs first. Then perform the Function Test of the scan tool in order to ensure proper operation of the ABS.
If DTCs C0269 or C0274 are setting after replacing the EBCM, check the vehicle for an auxiliary device (winch, auxiliary battery system, etc.) which could cause a voltage spike on the battery feed to the EBCM. If the vehicle does have an auxiliary device, install a Metallic Oxide Varistor (MOV) in the battery feed circuit to the EBCM.
Test Description
The numbers below refer to the steps in the diagnostic table:
-
This step determines the resistance of the power ground circuit.
-
This step determines the battery voltage available to the EBCM.
-
This step determines the resistance of the signal ground circuit.
-
This step determines the ignition voltage available to the EBCM.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
2 |
Is the connector in good condition? | -- | ||
Measure the resistance between terminal B of the 2-way EBCM harness connector and the ground using a J 39200 . Is the resistance measurement within the specified range? | 0-2ohms | |||
Measure the voltage between terminal A of the 2-way EBCM harness connector and the ground using a J 39200 . Is the voltage equal to or greater than the specified value? | 10.0 V | |||
5 | Inspect the grey fusible link. Is the grey fusible link open? | -- | ||
6 |
Is the connector in good condition? | -- | ||
Measure the resistance between terminal J of the 10-way EBCM harness connector and the ground using a J 39200 . Is the resistance measurement within the specified range? | 0-2ohms | |||
Is the voltage equal to or greater than the specified value? | 10.0 V | |||
9 | Inspect the 15-amp I-3 fuse. Is the fuse open? | -- | ||
10 | Malfunction is intermittent, perform the following:
Does the DTC set as a current DTC? | -- | Malfunction is intermittent. Go to Diagnostic Aids | |
11 | Repair the 2-way EBCM harness connector. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
12 | Repair the open or the high resistance in the CKT 350. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
13 | Repair the short to ground in the CKT 442. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
14 | Repair the open or the high resistance in the CKT 442. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
15 | Repair the 10-way EBCM harness connector. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
16 | Repair the open or the high resistance in the CKT 451. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
17 | Repair the short to ground in the CKT 241. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
18 | Repair the open or the high resistance in the CKT 241. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
19 | Replace the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
