Data Link Communication System: Other Oldsmobile Bravada III

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 High/Low-module is unable to distinguish between the two wiring conditions.
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.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT CONDITIONS AND POOR CONNECTIONS in Wiring Systems.

Data Link Connector (DLC)

The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following

1. Scan tool power battery positive voltage at terminal 16.
2. Scan tool power ground at terminal 4.
3. Class 2 serial data at terminal 2.
4. Common signal ground at terminal 5.

Class 2 Serial Data Line

The class 2 serial data line on this vehicle is a ring/star configuration. The BCM and PCM form the ring portion of the class 2 serial data circuit. If one of the class 2 serial data circuits to the BCM or PCM opens, communication will not be interrupted. The following modules communicate on the class 2 serial data line

1. The body control module (BCM)
2. The driver door module (DDM)
3. The electronic brake control module (EBCM)
4. The front passenger door control module (FPDM)
5. The HVAC control module
6. The inflatable restraint sensing and diagnostic module (SDM)
7. The instrument panel cluster (IPC)
8. The liftgate control module (LGM)
9. The memory seat module-driver w/power seat
10. The memory seat module-passenger w/power seat
11. The powertrain control module (PCM)
12. The radio
13. The radio amplifier
14. The RSA/HVAC control module-rear auxiliary
15. The theft deterrent control module w/Immobilizer
16. The transfer case shift control module w/4WD
17. The vehicle communication interface module (VCIM) w/UE1

The class 2 serial data line allows a scan tool to communicate with these modules for testing purposes, checking for DTCs, and to activate/enable/disable functions. These class 2 serial data circuits are bussed together via two splice packs and a data link connector (DLC)

1. SP205 - Located behind the I/P near the headlamp switch connector.
2. SP206 - Located in the body harness near the rear of the right rear seat under the carpet.
3. DLC - connects the scan tool to the class 2 serial data circuits.

Refer to Data Link Communications Component Views .