Scan Tool Does Not Communicate with Class 2 Device

SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE

CIRCUIT DESCRIPTION
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. Connecting a scan tool to the data link connector (DLC) allows communication with the modules for diagnostic purposes.

TEST DESCRIPTION

Step 1 - Step 10:

The numbers below refer to the step numbers on the diagnostic table.
2. A current DTC U1305 may be retrieved only from the body control module (BCM).
3. A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit. The following modules communicate on the class 2 serial data circuit. The BCM is diagnosed only through GMLAN serial data circuit.
- Body control module (BCM)
- Communication interface module (OnStar(r))
- Digital radio receiver (DRR)
- Driver door module (DDM)
- Driver door switch (DDS)
- Driver position module (DPM)
- Folding top controller (FTC)
- Head up display (HUD)
- HVAC control module
- Inflatable restraint sensing and diagnostic module (SDM)
- Instrument panel cluster (IPC)
- Passenger door module (PDM)
- Radio
- Remote control door lock receiver (RCDLR)
- Steering column lock control module (SCLCM)
7. Data link connector terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
9. A poor connection at splice pack SP205 will cause this condition but will not set a DTC.
10. An open in the class 2 serial data circuit between the DLC and splice pack SP205 will prevent the scan tool from communicating with any module on the class 2 network. This condition will not set a DTC.