Test A

PINPOINT TEST A: THE VEHICLE SECURITY MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

Test A1-A4:

Test A4-A5:

Normal Operation
The vehicle security module communicates with the diagnostic tool through the UART based protocol (UBP) communications network circuit 693 (OG). If circuit 693 (OG) becomes open or shorted to ground, communications to that module will not be possible. Check circuit 693 (OG) between the vehicle security module C3203f and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open in circuit 693 (OG), damage to the DLC C251, damage to the vehicle security module C3203f, or a problem in the in-line connectors.

The vehicle security module receives fused power through circuits 456 (DG/OG), 645 (WH/LB) and is grounded on circuit 1205 (BK).

Possible Causes
- Battery junction box (BJB) fuse 2 (30A)
- Central junction box (CJB) fuse 20 (5A)
- UBP circuit 693 (OG) shorted to ground or open
- circuit 645 (WH/LB) open or shorted to ground
- circuit 456 (DG/OG) open or shorted to ground
- circuit 1205 (BK) open
- DLC C251
- vehicle security module
- vehicle security module C3203d, C3203e, and C3203f