Circuit Description - DTC P3000 - Information Codes 123, 125: Notes

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

When using an OBD II scan tool other than TOYOTA hand-held tester, check all the steps.
When using TOYOTA hand-held tester, confirm the information code and check it.

The HV ECU gives warning to the driver and performs the fail safe control, according to the abnormal signal received from the battery ECU.