P1779

Schematic:

The Engine Control Module (ECM), Transmission Control Module (TCM), and the Body Control Module (BCM) communicate with each other over the Controller Area Network (CAN) BUS circuits 2500 and 2501. The CAN BUS is a communications protocol that is used by the TCM to communicate vital engine control inputs from a stand-alone engine controller. The diagnostic checks the information received in CAN to determine whether to pass or fail a code. Before checking the information, the TCM makes sure the CAN messages are being received by checking the BUS failure timer.

DTC PARAMETERS
DTC P1779 Will set if:
- Engine speed is greater than 500 rpm for 5 seconds and not at fuel cutoff.
- System voltage between 8 and 18 volts.

DIAGNOSTIC AIDS
- This code does not indicate a problem with the TCM. It does indicate the ECM is not sending the required information to the TCM.
- Determine the problem or look for trouble code(s) in the ECM.