HVAC Serial Data Circuit

The PCM uses the Class 2 serial data circuit to communicate with various other devices and systems in the vehicle. The PCM ensures that communication remains established by monitoring the serial data circuit for state of health messages from the other devices using the circuit. If the PCM detects a loss of the state of health serial data message from the HVAC Controller, DTC P1605 will set.

For information concerning the various devices that use the Class 2 serial data circuit, refer to Serial Data in Electrical Diagnosis.