DTC P1440 (57): Motor Power Inverter (MPI) Module Output Circuit Malfunction: General Description

An open in the gate-drive wire, an OFF failure of the motor power inverter (MPI) module, an open in the motor power cable, or an open in the motor coil causes a deviation from the target torque value of the drive motor. The motor control module (MCM) detects these system failures by monitoring each phase current change.

Malfunction Detection 1 (judgment by current deviation) (Figure)

An open in the gate drive-wire or in the motor power cable causes a decrease in the phase current, so the MCM calculates the target output value from the other two phases. A failed phase current value differs from the others. When a difference in phases is detected or if the ratio of the fluctuation range is a specified value for a specified time, a malfunction is detected and a DTC is stored.

Malfunction Detection 2 (judgment by deviation of electrical power) (Figure)

If normal voltage cannot get to the IMA motor because of open circuits in the gate drive-wires, an OFF failure of the MPI module, or a MCM circuit malfunction etc., there is a difference between the target electrical power and the actual motor electrical power. If the electrical deviation is a specified value for a set time, a malfunction is detected and a DTC is stored.