U2102
U2102 - U2103 - MORE/FEWER CONTROLLERS ON BUS THEN PROGRAMMEDTEST DESCRIPTION
Diagnostic Chart:
The controller area network (CAN) is a high speed system for sharing data. The circuit consists of a two wire twisted pair connecting the ECM to the TCM, a second twisted pair connecting the TCM to the EBTCM, and a third twisted pair connecting the EBTCM and BCM.
The CAN circuits are monitored continuously by the modules on the circuit. The only requirement is that the modules are in an On power mode.
Each controller on the CAN serial data circuit monitors the activity or traffic on the bus. The module setting the DTC does not receive CAN formatted messages from all of the modules it expected too, or receives more CAN formatted messages. This indicates that there may be fewer controllers or more controllers actively communicating on the bus than programmed. After the seventh attempt, the module sets one of the following DTCs:
^ U2102 - More Controllers
^ U2103 - Fewer Controllers
Besides storing the DTC as both current and history, the ECM takes actions as listed:
^ The ECM turns On the MIL during the second consecutive drive cycle with the error detected
^ Record the operating conditions at the time of turning on the MIL and store the data as freeze frame information.
The MIL is turned Off and the DTC cleared by the ECM if the fault is not detected for three consecutive drive cycles, the current DTC is cleared and the MIL is turned Off. The history DTC is cleared if the malfunction does not reoccur for 40 consecutive drive cycles.