Data Link Communications System: Other Pontiac Sunfire I

Conditions for Setting the DTCs

1. No valid messages are detected on the class 2 serial data circuit.
2. The voltage level detected on the class 2 serial data circuit is under one of the following conditions: High Low
3. The above conditions are met for approximately 3 seconds.

Action Taken When the DTCs Sets

1. The module inhibits the setting of all other class 2 DTCs.
2. The module uses default values for all parameters received on the class 2 serial data circuit.

Conditions for Clearing the DTCs

1. Current DTCs will clear when a valid class 2 message is detected on the class 2 serial data circuit or at the end of the current ignition cycle.
2. History DTCs will clear upon receipt of a scan tool Clear DTCs command.

Data Link Connector (DLC)

The data link connector (DLC) terminal 2 contains the class 2 serial data link.

The DLC also provides a power source and Signal Ground for the scan tool as follows

1. Battery voltage at the DLC terminal 16 (circuit 40)
2. Power Ground at terminal 4 (circuit 150)
3. Signal Ground at terminal 5 (circuit 451)

Class 2 Serial Data Link

The class 2 serial data link allows the following modules to communicate with each other

1. The body control module (BCM)
2. Digital radio receiver (DRR)
3. The electronic brake control module (EBCM)
4. The instrument panel cluster (IPC)
5. The radio
6. The powertrain control module (PCM)
7. The inflatable restraint sensing and diagnostic module (SDM)
8. Vehicle communication interface module (VCIM)

The class 2 serial data link allows a scan tool to communicate with the above modules for diagnostic and testing purposes.