Test M: No Universal Asynchronous Receiver-Transmitter (UART) Based Protocol (UBP) Communications Network Communication

PINPOINT TEST M: NO UNIVERSAL ASYNCHRONOUS RECEIVER-TRANSMITTER (DART) BASED PROTOCOL (UBP) COMMUNICATIONS NETWORK COMMUNICATION

M1:

M1-M4:

M5-M8:

M8-M11:

Normal Operation
The vehicle security module and the driver seat module (DSM) (if equipped) communicate with the diagnostic tool through the UBP communications network circuit 693 (OG). The instrument cluster is also on the UBP communications network, but does not utilize this network to communicate with the diagnostic tool. 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, DSM (if equipped), the instrument cluster and the data link connector (DLC) C251. The total resistance value 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, the DSM, instrument cluster, or a problem in one of the in-line connectors. If, after individual checks of each circuit leading to a module show resistance values less than 5 ohms and no in-line connector issues present, the diagnostic tool data link test must be run with the module in question disconnected. If the diagnostic tool data link test passes with the module in question disconnected it is the source of the concern and should be removed and a new module installed.

Possible Causes
- circuit 693 (OG) short to voltage, short to ground or open
- DLC C251
- vehicle security module
- instrument cluster
- DSM (if equipped)