Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P1440 (57): IMA System Problem: General Description
An open in the gate drive wire, an insulated gate bipolar transistor (IGBT) OFF failure, and an open in the motor power cable or in the motor coil causes a deviation from the target value of torque in the integrated motor assist (IMA) system. By monitoring changes in phase current when an abnormality occurs, the function monitor detects a malfunction in the IMA system. An open in the gate drive wire or in the motor power cable causes an increase in the other two normal phases. current to compensate for a decrease in the phase when the motor control range is not in the low speed range.
| Execution | Continuous |
| Sequence | Motor current U/V/W phase signal circuit, Battery module, Battery cell, Bypass contactor, Motor commutation sensor, Battery cell temperature signal circuit, Detection signal circuit, Battery current circuit, Motor current signal circuit, MPI, MDM, BCM, MCM |
| Duration | 0.512 seconds or more |
| DTC Type | One drive cycle, MIL ON, IMA system indicator ON |
| Condition | Minimum | Maximum |
|---|---|---|
| MCM power-supply voltage | 10.5 V | - |
| Motor speed | 2,000 rpm | - |
| Motor driving torque | 10 N.m (1 kgf.m, 7.2 lbf.ft) | - |
| Battery module voltage | 120 V | 192 V |
| No active DTCs | MPI, Motor current sensor, Battery module, Battery module temperature sensor, MCM, MDM, Bypass contactor, Motor commutation sensor, MDM voltage sensor, Battery current sensor, MPI module current sensor, MDM current sensor, BCM | |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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