Advanced Diagnostics

Advanced Diagnostics - DTC P1440 (57): Motor Control Module (MCM) Circuit Malfunction
















General Description
An open in the gate drive-wire, an insulated gate bipolar transistor (IGBT) OFF failure, differs from an open in the motor power cable, or an open in the motor coil which causes a deviation from the target value of motor output in the motor drive system. The motor control module (MCM) detects these system failures by monitoring the motor current (MC) sensor, the motor power inverter (MPI) module current sensor, and the MPI module voltage.

Malfunction Detection 1 (open in the gate drive wire, IGBT OFF failure) (Fig. 1)
- An open in the gate drive-wire or in the motor power (MP) cable causes a decrease in the phase current, so the MCM calculates the target output value from the other two phases. A bad phase current value differs from the others. When a difference in phases fluctuation range is detected or if the ratio of the fluctuation range is a specified value or less for more than the specified time, a malfunction is detected and a DTC is stored.
Malfunction Detection 2 (judgment by deviation of electrical power) (Fig. 2)
- If normal voltage cannot get to the motor because of open circuits in the gate drive-wires, an all IGBT OFF failure, or a MCM circuit malfunction etc., there is a difference between the direct current power to be consumed or regenerated (target electrical power) and the actual direct current power. If the electrical deviation is the specified value, a malfunction is detected and a DTC is stored.

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






Enable Conditions






Malfunction Threshold
Malfunction Detection 1
- The ratio of maximum to minimum for the three MC sensor fluctuation values becomes 70 % or less at least 48 times within 500 milliseconds.
Malfunction Detection 2
- The difference between the direct current power (target electrical power) and the actual direct current power is 2 kW or more for at least 500 milliseconds.

Driving Pattern
1. Start the engine.
2. Hold the engine at 4,000 rpm with no load (in P or N) until the IMA battery level gauge (BAT) indicates 2/3 segments or more.
3. Drive the vehicle with wide open throttle for at least 2 seconds.

- If you have difficulty duplicating the DTC, retest after turning off electrical components such as the audio system and A/C, and try a different gear position.
- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM and the MCM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.