Test B: The Driver Seat Module (DSM) Does Not Respond to The Diagnostic Tool

PINPOINT TEST B: THE DRIVER SEAT MODULE (DSM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

B1-B2:

B2-B4:

B4-B5:

Normal Operation
The DSM communicates with the diagnostic tool through the universal asynchronous receiver-transmitter (UART)-based protocol (UBP) network circuit 2077 (PK/LB). If circuit 2077 (PK/LB) becomes open or shorted to ground, communications to that module are not possible. Check circuit 2077 (PK/LB) between the DSM C341c and the data link connector (DLC) C251. The total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open in circuit 2077 (PK/LB), damage to the DLC C251, damage to the DSM C341c, or a problem in the in-line connectors.

The DSM fused power (overload protected) is supplied through the following bussed electrical center (BEC) fuses: 10 (30A), circuit 566 (DG), and fuse 51 (10A) on circuit 1567 (RD/LB). The DSM ground circuits are circuit 1203 (BK/LB) and 1205 (BK).

Possible Causes
- BEC fuses:
- 10 (30A)
- 51 (10A)
- UBP circuit 2077 (PK/LB) open
- circuit 1567 (RD/LB), open or shorted to ground
- circuit 566 (DG), open or shorted to ground
- circuit 1203 (BK/LB) open
- circuit 1205 (BK) open
- DLC C251
- DSM