C1275

DTC C1275 PCM Serial Data Malfunction (Part 1 Of 2):

DTC C1275 PCM Serial Data Malfunction (Part 2 Of 2):

PCM Serial Data Schematic:

CIRCUIT DESCRIPTION
The UART serial data 1ink allows information to be exchanged from module to module as needed. This is done by the PCM, the PCM requests and sends all the information that is transmitted on the UART line. When a scan tool is connected to the UART line it takes over for the PCM and sends and requests the needed information.

CONDITION FOR SETTING THE DTC
- DTC C1275 can set anytime the ignition is on and a message has not been received from the PCM for 7.0 seconds.

ACTION TAKEN WHEN THE DTC SETS
- A malfunction DTC is stored, TCS is disabled and the "TRACTION OFF" indicator lamp is turned "ON." ABS remains functional.

CONDITIONS FOR CLEARING DTC
- Condition for DTC is no longer present and scan tool clear DTC function is used.
- 50 ignition cycles have passed with no DTC(s) detected.

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.

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