C1275

CIRCUIT DESCRIPTION
The serial data UART allows information to be exchanged from module to module as needed. This is done by the PCM. The PCM requests and sends all of the information that is transmitted via serial data UART. When the scan tool is connected to the serial data UART, the scan tool takes over for the PCM and sends and requests the needed information.

CONDITIONS FOR SETTING THE DTC
All of the following conditions occur:
^ The ignition is ON.
^ A serial data UART message has not been received for 7 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ A malfunction DTC is stored.
^ The TCS is disabled.
^ The TRACTION OFF indicator is turned ON.
^ The ABS remains functional.

CONDITIONS FOR CLEARING THE DTC
^ The condition for the DTC is no longer present and you used the scan tool Clear DTC function.
^ The EBCM/EBTCM does not detect the DTC in 50 drive cycles.

DIAGNOSTIC AIDS
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.
^ If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Diagnostic Information and Procedures.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
5. This step checks for a short to ground.
7. This step checks for an open in CKT 800.
11. This step checks for a short to voltage.