Monitor Description

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