Monitor Description

The hybrid vehicle control ECU assembly performs many diagnostic tests to verify proper operation of internal ECU systems. In one of these tests, the hybrid vehicle control ECU assembly checks the communication bus off count and the message register of the CAN (Controller Area Network) controller. If the hybrid vehicle control ECU assembly detects an error in the communication bus off count or message register, it will conclude that there is an internal malfunction and will illuminate the MIL and store a DTC.