Circuit Description
The electronic brake control module (EBCM) is required to operate within a specified range of voltage to function properly. During antilock brake system (ABS) and traction control system (TCS) operation, there are current requirements that will cause the voltage to drop. Because of this, voltage is monitored out of ABS/TCS control to indicate a good charging system condition, and also during ABS/TCS control when voltage may drop significantly. The EBCM also monitors for high voltage conditions which could damage the EBCM.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0896 System High/Low Voltage
Conditions for Running the DTC
The vehicle speed is above 6.4 km/h (4 mph).
Conditions for Setting the DTC
The battery voltage drops below 9.4 volts or exceeds 17.4 volts.
Action Taken When the DTC Sets
| • | The ABS telltale will be turned ON. |
| • | The ABS control module will disable the ABS, the TCS, and the dynamic rear proportion (DRP). |
Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Diagnostic Aids
Important: If the battery voltage returns to normal levels 9.4-17.4 volts within the same ignition cycle, the ABS control module will enable ABS/TCS/DRP and will turn the ABS telltale OFF.
Use the scan tool to observe the battery voltage display.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the DTC set? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the battery voltage below the specified value? | 12.6 V | Go to Step 4 | Go to Diagnostic Aids |
4 | Using the scan tool, monitor the battery voltage in the engine control module (ECM) data list. Is the battery voltage below the specified value? | 12.6 V | Go to Charging system | Go to Step 5 |
5 | Test the battery positive voltage circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 |
6 | Replace the electronic brake control module (EBCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
