DTC P0856
Diagnostic Instructions
DTC Descriptor
DTC P0856 00: Traction Control Torque
Request Circuit Malfunction
Circuit/System Description
When traction control is active, the electronic brake control
module (EBCM) sends a serial data message to the engine
control module (ECM) requesting torque reduction. When certain
ECM DTCs are set, the ECM will not be able to perform the torque
reduction for traction control. A serial data message is sent to
the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
Engine running
Conditions for Setting the DTC
The ECM detects a fault that prevents it from performing a
traction control function and sends a serial data message to the
EBCM indicating that torque reduction is not allowed.
Action Taken When the DTC Sets
| • |
The EBCM disables the traction control and
stability control for the duration of the ignition cycle. |
| • |
The traction control/stability control-active
indicator turns ON. |
Conditions for Clearing the DTC
| • |
A current DTC clears when the diagnostic runs and
passes. |
| • |
The EBCM will turn OFF the indicator in the next
ignition cycle. |
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Verify that no DTCs except P0856 00 are present
in the ECM.
- Replace the K20 Engine Control Module and verify
the DTC does not reset.
| ⇒ |
If the DTC resets replace the K17 Electronic
Brake Control Module (EBCM). |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for control module replacement, setup
and programming
|
