Circuit Description
When the EBCM commands the ABS enable relay ON, the ABS supplies battery voltage to the EVO actuator terminal A . The EBCM terminal 18 provides the ground for the EVO actuator through the actuator terminal B. The EBCM controls the amount of current supplied to the EVO actuator based on input from the ABS wheel speed sensors and the steering wheel position sensor.
Conditions for Setting the DTC
| • | DTC C1274 can be set anytime after the ABS initialization. |
| • | A malfunction exists if an excessive voltage drop is across the EVO actuator driver. |
Action Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The VES is disabled and power steering returns to full assist. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | DTC C1274 setting conditions no longer exist. |
| • | The ignition key is turned to the OFF position. |
Clearing VES DTCs will automatically clear ABS DTCs resulting in a loss of DTC history data. Refer to Diagnostic Aids.
Diagnostic Aids
The EVO actuator is malfunctioning. Use the enhanced diagnostic function of the scan tool to verify the frequency of a malfunction. Refer to Enhanced Diagnostics in ABS/ETS.
An open or short to voltage exists in any of the EVO actuator circuit wires. When diagnosing for an intermittent short or an open, massage the wiring harness while watching the test equipment for changes.
An intermittent malfunction is most likely caused by one of the following conditions:
| • | A poorly connected wire |
| • | A wire that has rubbed through the insulation |
| • | A wire that is broken inside the insulation |
| • | A backed out terminal |
| • | An improper mating |
| • | A broken lock |
| • | An improperly formed or damaged terminal |
| • | A poor terminal to wiring connection |
| • | A sign of physical damage to the wiring harness |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check |
2 |
Is the voltage within the specified range? | 0-1 V | Go to Step 3 | Go to Step 6 |
3 |
Is the resistance within the specified range? | 7-19 ohms | Go to Step 4 | Go to Step 5 |
4 |
Is DTC C1274 set as a current DTC? | -- | Go to Step 10 | Go to Step 8 |
5 |
Is the resistance within the specified range? | OL (Infinite) | Go to Step 9 | Go to Step 7 |
6 | Repair the short to voltage in CKT 1295. Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
7 | Repair the short between CKT 1295 and CKT 1633/855. Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
8 | Is the malfunction intermittent? | -- | Go to the Diagnostic Aids for this DTC | -- |
9 | Replace the EVO actuator. Refer to Variable Effort Steering Actuator Replacement . Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
10 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement in Antilock Brake System. Did you complete the repair? | -- | Go to Diagnostic System Check | -- |
