2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 2701
5. Ignition ON, connect a 3A fused jumper wire between terminal 3 on the DT-47825-10 - jumper harness and ground at the transmission case.
Verify with a scan tool the Park/Neutral parameter displays Park/Neutral.
瀚慖f the Park/neutral parameter displays In Gear, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the
K20 ECM.
6. Ignition OFF, disconnect the DT-47825-10 - jumper harness from the X1 vehicle harness connector.
7. Connect the X1 vehicle harness connector to the Q8 control solenoid valve assembly.
8. Remove the transmission fluid pan. Refer to Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement ().
9. Disconnect the B15 automatic transmission internal mode switch electrical connector from the K71 TCM.
10. Ignition ON, test for 11-13 volts between terminal F on the K71 TCM and ground at the transmission case.
瀚慖f not within the specified range, replace the Q8 control solenoid valve assembly.
11. If all circuits test normal, replace the B15 automatic transmission internal mode switch.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Control Module References (See: Testing and Inspection/Programming and Relearning)for control solenoid valve assembly or ECM
replacement, setup, and programming.
Note: If the IMS switch has been replaced, inspect the valve body detent spring to be sure it is centered over the detent lever. This prevents
the detent spring from hitting the IMS switch.
* Manual Shift Shaft Position Switch Replacement (See: Powertrain Management/Computers and Control Systems/Sensors and Switches -
Computers and Control Systems/Transmission Position Sensor/Switch/Service and Repair/6L45/6L50/6L80/6L90 - Automatic Transmission
)for IMS replacement.
P0856
DTC P0856
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0856
- Engine Control Module (ECM) Traction Control Torque Request Circuit
Circuit/System Description
The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control. The EBCM sends
a serial data message to the 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
* Ignition ON.
* The ignition voltage is greater than 10 volts.
Conditions for Setting the DTC
The ECM diagnoses a condition preventing the engine control portion of the 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 for the duration of the ignition cycle.
* A DIC message and/or a warning indicator may be displayed.
