Monitor Description
WARNING: This page is about a different car, the 2004 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
The HV control ECU performs diagnostic monitoring to verify proper operation of internal and external ECU systems. In this diagnostics monitor, the HV control ECU checks the REF signal from the motor main ECU for errors.
If the HV control ECU detects an error in the REF signal, it will conclude that there is a malfunction in the motor main CPU, the REF signal or the HV control ECU. The HV control ECU illuminates the MIL and sets a DTC.