RL V6-3.7L (2009)
4. The communication circuit test is passed.
Since the door lock switch message was received by all the ECUs expecting to receive a message, the communication circuit between those units is OK.
There are multiple messages sent and received by each ECU during this time to insure that the communication circuit is intact.
Failed circuit
5. Turn the ignition switch to ON (II).
6. The driver's MPCS unit transmits a door lock switch message.
7. The MICU, relay control module, gauge control module, and keyless access control unit expect to receive the door lock switch message, but since
there is a break in the communication circuits, it is not received.
8. Each ECU that expects to receive the door lock switch message from the driver's MPCS unit will transmit DTCs for the message that it did not
receive.
Since there is a break in the communication circuit, the door lock switch message could not be received by the MICU, the relay control module, the
gauge control module, or the keyless access control unit. Each of these units will set "loss of communication" error codes for the message(s) they did not
receive. There may be multiple communication DTCs if the unit that has become disconnected from the network would normally transmit multiple
messages during the communication line test. For example, the driver's MPCS unit sends the door switch message and door lock switch message during
the communication circuit test.
Diagnostic Trouble Codes (DTC)
There are three types of DTCs used by the CAN networks.
B-CAN System Unit Input/Output Index
