If almost all of the DTCs of the main body ECU are stored, the possibility of a communication stop of the
main body ECU is high.
When a CAN communication error occurs, many DTCs are output. DTCs other than communication error
DTCs (such as DTCs that start with C or B) and communication DTCs for the ABS system are important
DTCs, however it may be easier to determine the malfunctioning part by examining the overall situation
without considering these DTCs.
(b) To help determine the part of the sub bus that has a communication error, prioritize the communication stop
DTCs stored in the gateway function equipped ECU.
Text in Illustration
*a Items to be Checked *b ECM
*c Gateway Function Equipped ECU *d Location of Malfunction
*e V Bus *f Sub Bus
This DTC table is from another model, and is only used here to show the ECUs connected to both a V bus
and a sub bus. It shows DTCs output when there is an open in the main bus lines for the ECM on the sub
bus. This table does not show DTCs applicable to this vehicle.
As gateway function equipped ECUs (sub bus monitor ECU) monitor signals from all ECUs that are
connected to sub buses, gateway function equipped ECUs can detect ECUs with a communication stop more
When there is a communication stop for the gateway function equipped ECU (gateway), communication with
ECUs connected to other buses such as the V bus stops. Therefore, communication DTCs for ECUs
connected to other buses are also stored.
(c) When any of the following malfunctions occurs, many DTCs are likely to be output from many ECUs.
Because of this, it may be difficult to determine the probable malfunctioning part.