Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC C0901: Device 2 Voltage Low - EBCMDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IGN I | C0901 | C0901 | -- | -- |
Ground | -- | C0901 | -- | -- |
Circuit/System Description
The electronic brake control module (EBCM) monitors the ignition voltage level available on the ignition 1 circuit fed by the ABS/VSES fuse 29. A low voltage condition prevents the system from operating properly. If the EBCM detects low voltage on the ignition 1 circuit, DTC C0901 will set.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle speed is greater than 3 km/h (1.8 mph) |
Conditions for Setting the DTC
The EBCM detects that the ignition voltage is less than 6.5 V for 7 seconds.
Action Taken When the DTC Sets
The BRAKE indicator turns ON.
Conditions for Clearing the DTC
| • | The DTC will pass when the ignition voltage is greater than 6.5 V for 1 second. |
| • | The EBCM automatically clears a history DTC when a current DTC is not detected in 100 consecutive ignition cycles. |
Diagnostic Aids
A low voltage DTC in multiple modules indicates a concern in the charging system.
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 V.
- Ignition OFF, disconnect the harness connectors at the EBCM.
- With the ignition OFF and the scan tool disconnected, open and close the driver door, and wait 30 seconds. Test for less than 5 Ω between the ground circuit terminals listed below and ground.
- Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.
- Verify that a test lamp illuminates between the ignition circuit terminals listed below and ground.
- If all circuits test normal, replace the EBCM.
| ⇒ | If not within the specified range, refer to Charging System Test. |
| • | Terminal 4 X1 |
| • | Terminal 1 X2 |
| • | Terminal 32 X2 |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| • | Terminal 2 X1 |
| • | Terminal 2 X2 |
| • | Terminal 31 X2 |
| • | Terminal 1 X1 |
| • | Terminal 46 X2 |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for EBCM replacement, setup, and programming.
