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

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

Test K1-K2:

Test K3-K5:

Test K5 Continued:

Test K5-K9:

Test K10-K12:

Normal Operation
The driver seat module (DSM), the electronic automatic temperature control (EATC) module, the instrument cluster and the vehicle security module all communicate with the diagnostic tool through the UBP communications network circuit 1906 (VT). If circuit 1906 (VT) becomes open or shorted to ground, communications to that module is not possible. Check circuit 1906 (VT) between the DSM, the EATC module, the instrument cluster, the vehicle security module 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 1906 (VT), damage to the DLC C251, damage to the DSM, the EATC module, the instrument cluster, the vehicle security module 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 data link diagnostics test must be ran with the module in question disconnected. If the data links diagnostics 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 1906 (VT) short to voltage, short to ground, or open
- in-line connector
- DLC C251
- DSM C341c
- DSM
- EATC module C228b
- EATC module
- instrument cluster C220a
- instrument cluster
- vehicle security module C3008b
- vehicle security module