Advanced Diagnostics

Advanced Diagnostics - DTC P0AA7 (76): Motor Control Module (MCM) Internal Circuit Malfunction






General Description
There is a voltage monitor circuit for the battery module in the motor control module (MCM). The voltage is monitored by the photoMOS relay on the voltage monitor circuit. When two detections are judged for a specified cycle, a malfunction is detected and a DTC is stored.

1. PhotoMOS2 or photoMOS3 ON failure detection
The MCM confirms voltage by switching photoMOS2 or photoMOS3 to ON with the voltage monitoring capacitor charged. If the confirmed voltage is a specified value, photoMOS2 or photoMOS3 is judged as a failure.

2. PhotoMOS1 or photoMOS4 ON failure detection
The MCM confirms voltage by switching photoMOS1 or photoMOS4 to ON with the voltage monitoring capacitor discharged from the charged condition (from above condition). If the confirmed voltage is a specified value, photoMOS1 or photoMOS4 is judged as a failure.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
Either photoMOS1, photoMOS2, photoMOS3, or photoMOS4 voltage is 31.5 V or more and this condition is detected at least 10 times.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the MCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.