P0AF6

What it means

P0AF6 means the hybrid or electric vehicle control unit has seen the signal from drive motor inverter temperature sensor B jumping around, dropping out or reading implausibly. The inverter converts high-voltage battery power to drive the motor, and the control unit relies on this sensor to protect it from overheating. An unreliable reading means it cannot trust the inverter temperature, so it logs the fault and may limit power.

Symptoms

• Hybrid or EV system warning light on, sometimes with the main warning light
• Reduced power or limp mode, especially under load
• Fault that comes and goes, or appears after bumps or heat cycles
• Cooling fan or pump running harder than expected
• Reduced regenerative braking or assist
• In rare cases, the car will not enter Ready mode

Possible causes

• Loose, corroded or damaged connector or terminals at the inverter temperature sensor circuitlikely
• Chafed, broken or intermittently shorted wiring between the sensor and the control unitlikely
• Faulty inverter temperature sensor, usually internal to the inverter assemblypossible
• Moisture or coolant contamination in the connector or inverter housingpossible
• Inverter or motor control unit internal fault affecting sensor readingsrare
• Low or poor inverter coolant flow causing real temperature swings that look erraticrare

How to diagnose

1. Only trained technicians with high-voltage safety training should work on these systems; follow the manufacturer's isolation procedure before touching any orange cables or the inverter.
2. Read all stored codes and freeze frame data, noting temperature, speed, load and whether other inverter or motor temperature codes are present.
3. Check live data for inverter temperature sensors and compare sensor B with the others and with coolant temperature on a cold car; look for spikes or dropouts.
4. Inspect the sensor wiring and connectors for damage, corrosion, moisture, bent pins and poor terminal tension, gently wiggling the harness while watching live data.
5. Check the inverter cooling system: coolant level, pump operation, hoses and any air locks, following the model-specific procedure.
6. Test the sensor circuit for resistance, reference voltage, signal and ground against manufacturer data; the layout and values depend on the model.
7. Check for software updates or technical bulletins for the specific model and fault.
8. Clear the code and road test, confirming the fault does not return and the live data stays smooth.

How to fix

• Clean, repair or replace the damaged connector or terminals, and secure the harness properly
• Repair or replace the damaged section of wiring
• Replace the inverter temperature sensor or inverter assembly if the sensor is not serviceable separately, as the manufacturer specifies
• Dry out and repair any moisture ingress, and fix the source of the leak
• Restore correct inverter coolant level and flow, bleeding the system as the manufacturer specifies
• Update the control unit software only if an outdated calibration is a known cause for this model

Can I keep driving?

Nearby codes

• P0AF5GenericDrive Motor Inverter Temperature Sensor B Circuit High
• P0AF7Generic14 Volt Power Module Internal Temperature Too High