P0AEF
Drive Motor Inverter Temperature Sensor A Circuit Low.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- A
- AreaHybrid propulsion
- EF
- FaultThe specific fault in that area
What it means
P0AEF means the hybrid or electric vehicle control unit has seen the signal from drive motor inverter temperature sensor A fall below its expected range. This usually points to a short to ground, a shorted sensor or a fault in the sensor circuit. The control unit can no longer trust the inverter temperature reading, so it may reduce power to protect the inverter.
Symptoms
- Warning light on the dashboard, such as the hybrid or EV system warning or malfunction indicator
- Reduced power or limp mode
- Reduced or no electric motor assistance
- Inverter cooling fan or pump running constantly (model dependent)
- Car refuses to enter ready mode or shuts down the drive system
- Other inverter or hybrid system codes stored alongside
Possible causes
- Inverter temperature sensor internal fault (shorted or reading too low)likely
- Sensor signal wire shorted to ground or to another low-voltage wirelikely
- Damaged, corroded or wet connector at the inverter or control unitpossible
- Chafed or damaged wiring harness near the inverter or its bracketspossible
- Fault in the inverter control board or motor control unit input circuitpossible
- Outdated control unit software where the manufacturer has issued a fix (model dependent)rare
How to diagnose
- Read all stored and pending codes and record the freeze frame data, noting inverter temperature and vehicle state when the fault set.
- Check for related codes, such as other temperature sensor, inverter cooling or motor control faults, and treat any cooling faults first.
- With the car cold and off for some time, compare live inverter temperature sensor A with ambient and other temperature readings; a value stuck at an extreme low reading suggests a circuit fault.
- Visually inspect the low-voltage wiring and connectors to the inverter for chafing, water ingress, corrosion and bent or pushed-back pins. Do not touch or unplug high-voltage components unless trained and the system is isolated.
- Following the manufacturer's procedure, check the sensor circuit for a short to ground and measure the reference and signal voltages at the control unit connector.
- Wiggle-test the harness with live data on screen to see if the reading jumps or recovers.
- Check the sensor resistance against manufacturer specification where the sensor is accessible; on many models it is built into the inverter, so check the service information for your model.
- Check for available software updates or technical bulletins for the model and engine or drive system.
How to fix
- Repair any shorted, chafed or damaged wiring and secure the harness away from sharp edges and heat.
- Clean, dry or replace corroded or damaged connectors and terminals.
- Replace the inverter temperature sensor if it is a serviceable item and tests faulty.
- Replace or repair the inverter assembly if the sensor is integral or the control board is at fault, as per manufacturer procedure.
- Update the control unit software only if the manufacturer lists it as a fix for this fault.
- Clear the code after repair and road test to confirm it does not return.
Can I keep driving?
The car may be driven carefully for a short time if it runs normally, but expect reduced power or a sudden shutdown of the drive system. Stop and seek help if a red warning appears, power is lost, or the car overheats, and get it diagnosed soon by someone trained on high-voltage systems.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.