U1040 Loss of EBCM/EBTCM Communication - IPC

DTC U1040 Loss Of EBCM/EBTCM Communication:

DTC U1040 Loss Of EBCM/EBTCM Communication (Part 1 Of 2):

DTC U1040 Loss Of EBCM/EBTCM Communication (Part 2 Of 2):

CIRCUIT DESCRIPTION
The instrument cluster receives a State of health message from modules whose source IDs it has learned. if the instrument cluster does not see a state of health message from the Electronic Brake Control Module/Electronic Brake Traction Control Module (EBCM/EBTCM), a Diagnostic Trouble Code (DTC) will set.

CONDITIONS FOR SETTING THE DTC
The instrument cluster does not receive a state of health message from the EBCM/EBTCM.

ACTION TAKEN WHEN THE DTC SETS
^ Stores a DTC U1040 in the instrument cluster memory.
^ SERVICE VEHICLE SOON will be displayed for this DTC.

CONDITIONS FOR CLEARING THE DTC
^ Under all fault conditions, the ignition must be cycled before this DTC can change from current to history.
^ The instrument cluster detects a state of health message from the EBCM/EBTCM.
^ A history DTC will clear after 100 drive cycles if the condition for the malfunction is no longer present.
^ Using a scan tool.

DIAGNOSTIC AIDS
The following conditions may cause an intermittent malfunction to occur:
^ An intermittent open or short to ground in circuit 1122.
^ Poor connections at the instrument cluster. or the EBCM/EBTCM.

TEST DESCRIPTION
Numbers below refer to the step numbers on the diagnostic table.
1. Always perform the Instrument Cluster Diagnostic System Check before attempting to diagnose a DTC U1040.
2. The scan tool tries to communicate with the EBCM/EBTCM.
3. The scan tool tries to communicate with the other module.
4. This test checks for a poor connection at the EBCM/EBTCM.
6. This test checks for an open in circuit 1122.
7. This test checks for a short to ground in circuit 1122.