What Does P0AEF Mean?
The motor controller has detected that the drive motor inverter temperature sensor A circuit voltage is below the minimum expected threshold. In an NTC thermistor circuit, low voltage corresponds to very low resistance, which typically indicates either a shorted sensor, a short to ground in the wiring, or an extreme over-temperature condition. The motor controller will interpret this as a dangerously high temperature and will heavily derate or shut down the electric drive.
Safety Warning
The motor controller will severely limit or disable electric drive to protect the inverter from perceived overheating. If this is a genuine over-temperature, continued operation risks permanent IGBT module destruction. If the sensor is simply shorted, the vehicle will be unnecessarily disabled. In either case, have the system inspected before resuming normal operation.
Common Causes
30%
Internally shorted NTC thermistor (near-zero resistance)
30%
Short to ground in the sensor wiring harness
20%
Moisture intrusion at the sensor connector causing conductive bridge
15%
Genuine inverter over-temperature due to cooling system failure
5%
Motor controller analog input circuit failure pulling signal low
Diagnostic Steps
1
Read the reported inverter temperature A value. If it shows an extremely high temperature (above 100C) while the vehicle has not been under heavy load, the fault is likely electrical rather than thermal.
2
Disconnect the sensor and measure its resistance. A shorted sensor will read near 0 ohms. Normal NTC resistance at 25C is typically 5K-50K ohms. If shorted, replace the sensor.
3
With the sensor disconnected, measure insulation resistance from each sensor wire to chassis ground and to the motor housing. Less than 100K ohms indicates a short to ground in the harness.
4
Inspect the sensor connector for moisture, coolant contamination, or corrosion that could bridge the pins. The inverter environment is subject to heat cycling and potential coolant leaks.
5
If a genuine over-temperature is suspected, check the inverter cooling system — verify coolant pump operation, flow rate, coolant level, and condition of the coolant (degraded coolant loses heat transfer efficiency).
Estimated Repair Cost
$150 - $1,800
Parts + labor, varies by vehicle and location
The motor controller has detected that the drive motor inverter temperature sensor A circuit voltage is below the minimum expected threshold. In an NTC thermistor circuit, low voltage corresponds to very low resistance, which typically indicates either a shorted sensor, a short to ground in the wiri...
The most common cause of P0AEF (Drive Motor Inverter Temperature Sensor "A" Circuit Low) is: Internally shorted NTC thermistor (near-zero resistance)
Typical repair costs for P0AEF range from $150 to $1,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The motor controller will severely limit or disable electric drive to protect the inverter from perceived overheating. If this is a genuine over-temperature, continued operation risks permanent IGBT module destruction. If the sensor is simply shorted, the vehicle will be unnecessarily disabled. In either case, have the system inspected before resuming normal operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0AEF to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid/EV Drive Motor & Inverter
Difficulty
Type
Generic (SAE)
Recommended Tools
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