UART DATA LINE
The UART serial data communication relies on a 5 volt digital signal for the exchange of data between different control modules and a scan tool. When the ignition is in RUN and there is no data transmission, there is a constant 5 volts on the data line. Communication on the line brings the voltage to 0 volts. The supplemental restraint Sensing and Diagnostic Module (SDM) communicates on the UART data line.
CLASS 2 DATA LINE
Modules on the class 2 data line transmit state of health messages every two seconds to indicate proper functioning to other modules on the data line. Some modules recognize when other modules are not communicating. A Diagnostic Trouble Code (DTC) may be stored by a module that detects five seconds of non-communication from another module. Data line DTCs begin with the letter "U" and may be caused by faulty data line wiring, faulty module power or ground or a faulty control module.
ENTERTAINMENT & COMFORT BUS
The entertainment and comfort bus allows the radio receiver to communicate with a scan tool when connected to the DLC.
REMOTE CONTROL DOOR LOCK RECEIVER PROGRAMMING
The remote control door lock receiver may be programmed by a scan tool when connected to the DLC.
SELECTABLE TRANSFER CASE CONTROL MODULE
The selectable Transfer Case Control Module (TCCM) has limited self diagnostic capabilities and may be accessed by a scan tool when connected to the DLC.
SYSTEM TESTS
| WARNING | Vehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see AIR BAG RESTRAINT SYSTEMS - WITH SIDE AIR BAG or AIR BAG RESTRAINT SYSTEMS - WITHOUT SIDE AIR article in RESTRAINTS. |