Open circuit or high resistance in the sensor signal or return wiring; Corroded, loose or damaged connector terminals at the sensor or inverter; Faulty inverter temperature sensor (often built into the inverter assembly); Signal wire shorted to a voltage supply; Coolant or moisture ingress affecting the connector or inverter electronics; Fault inside the inverter or motor control unit.

P0AF0

Drive Motor Inverter Temperature Sensor A Circuit High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
A: AreaHybrid propulsion
F0: FaultThe specific fault in that area

What it means

P0AF0 means the hybrid or electric vehicle control unit sees the signal from drive motor inverter temperature sensor A at a voltage higher than the normal range. This usually points to an open circuit, a short to voltage, or a faulty sensor, so the control unit cannot trust the inverter temperature reading. It may limit power to protect the inverter.

Symptoms

Warning lamp on the dash, such as the hybrid system or powertrain fault light
Reduced power or limp-home mode
Reduced or no electric drive assistance
Reduced regenerative braking or charging performance
Cooling fan or pump running harder than normal
Car refuses to enter ready mode in some cases

Possible causes

Open circuit or high resistance in the sensor signal or return wiringlikely
Corroded, loose or damaged connector terminals at the sensor or inverterlikely
Faulty inverter temperature sensor (often built into the inverter assembly)possible
Signal wire shorted to a voltage supplypossible
Coolant or moisture ingress affecting the connector or inverter electronicspossible
Fault inside the inverter or motor control unitrare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting any other inverter, motor or cooling system codes
Check live data for inverter temperature A and compare it with other temperatures such as coolant and ambient after a cold soak; a reading stuck at an extreme suggests a circuit fault
Visually inspect the sensor harness and connectors for chafing, corrosion, water, bent pins or previous repair damage, following the manufacturer's high voltage safety precautions
Check the inverter coolant level and condition, and that the inverter cooling pump runs, as the procedure depends on the model
Have a high voltage trained technician isolate the system as per the manufacturer's procedure before testing the sensor resistance against specification
Check the reference voltage, signal and earth at the connector for open circuits or shorts to voltage using the wiring diagram
Wiggle test the harness with live data on display to find an intermittent fault
After repair, clear the codes and road test to confirm the code does not return

How to fix

Repair or replace damaged wiring and ensure the connector terminals are clean, secure and sealed
Replace the connector or terminals if corroded or damaged
Replace the temperature sensor if it is available separately; on many models it is part of the inverter assembly, so follow the manufacturer's guidance
Repair the short to voltage by finding and fixing the damaged harness section
Repair or replace the inverter or control unit only after wiring and sensor faults have been ruled out, per the manufacturer's procedure

Can I keep driving?

Medium severity

The car can often be driven carefully for a short time, but power may be limited and inverter overheating protection may be compromised. Book it in soon, and stop driving if a red warning appears, power drops sharply or the car will not drive normally.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.