U1040

Diagnostic Trouble Code (DTC) Chart:

Wiring Schematic:

CIRCUIT DESCRIPTION
Class 2 control modules receive a state of health message from the Electronic Brake Traction Control Module (EBTCM) through the Class 2 serial data link.

CONDITIONS FOR SETTING THE DTC
Class 2 control modules do not receive a state of health message from the EBTCM.

ACTIONS TAKEN WHEN THE DTC SETS
^ Class 2 control modules store DTC U1040 in memory.
^ The ABS indicator lamp turns on while the fault is present

CONDITIONS FOR CLEARING THE DTC
^ DTC U1040 will clear as a current DTC U1040 and will set as a history DTC U1040 when the class 2 control modules detect a state of health message from the EBTCM.
^ 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 or 1037.
^ Poor connections at the EBTCM.
^ An intermittent open in the Splice Pack SP205.
^ The Body Control Module (BCM) may store DTC U1040 if certain diagnostics are performed between the EBTCM and the Data Link Connector (DLC).
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control Module (BCM) disconnected. When BCM diagnostics and repairs are completed, refer to Computers and Control Systems Testing for additional information on PCM related DTCs.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. This step checks for an open in the Splice Pack 5P205.
2. This step checks for a short to ground in circuit 1122.
3. This step checks for a short to B+ in circuit 1122.
4. This step checks for an open in circuit 1122.