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 result of the ECM self-test. If the hybrid vehicle control ECU detects a "Fail" from the ECM self-test, it will conclude that there is an internal malfunction in the ECM. The hybrid vehicle control ECU will illuminate the MIL and set a DTC.