01 Decoding the Engine Control Unit (ECU): Inputs, Outputs, an… • 02 Top Reasons 8 Your Key Won't Turn in the Ignition & Easy Fi… • 03 This Is Why Mixing Fuel Grades Or Pumping The Wrong Fuel De… • 04 How to Reset a Car Computer After Replacing the Battery • 05 Inside the Day of an Automotive Engineer: Roles, Responsibi… • 06 The Underestimated Component That Eats Fuel Faster Than Any… • 07 Ford vs Toyota: Two Completely Different Definitions of Rel… • 08 B1700 – Body Network Communication Fault: Module Data Loss • 09 What Happens When Fuel Burns Inside a Cylinder • 10 What Happens If You Ignore Wheel Bearing Noise? •

DTC codes / P0Axx · Hybrid propulsion / P0AF0

P0AF0Drive Motor Inverter Temperature Sensor A Circuit High

P0AF0 indicates that the inverter's temperature sensor A circuit is reporting a voltage higher than the manufacturer's expected range, which the computer interprets as an open circuit or a short to voltage. This sensor monitors the drive motor inverter's temperature to protect the hybrid or electric drive system from overheating.

SystemPowertrain
Code typeGeneric (all makes)
SeverityHigh
Fix difficultyProfessional
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Reduced power output or limp mode to protect the inverter
  • Possible shutdown of the hybrid system while driving
  • Often no symptoms besides the warning light
  • In rare cases, overheating warnings or smell of hot electronics

Common causes, most likely first

  1. Faulty inverter temperature sensor A
  2. Open or shorted wiring in the sensor circuit
  3. Corroded or loose electrical connector at the sensor or inverter
  4. Damaged or chafed harness causing a short to voltage
  5. Failed inverter control module or internal circuit fault
  6. Poor ground connection for the sensor circuit

How to diagnose and fix it

  1. Scan all modules for stored codes and freeze-frame data to confirm P0AF0 and check for related codes
  2. Visually inspect the sensor connector and wiring for damage, corrosion, or loose pins
  3. Measure sensor resistance and compare to manufacturer's specification
  4. Back-probe the sensor signal circuit to check for an open or short to voltage
  5. Check the sensor's ground circuit for excessive resistance
  6. If wiring and sensor test good, diagnose the inverter control module or internal sensor circuit
  7. Clear codes and perform a road test to verify the repair

Inverter temperature sensor circuit pitfalls

  • A high voltage reading on the sensor circuit often results from a simple unplugged connector or a broken wire, not a failed sensor.
  • The inverter temperature sensor is sometimes integrated into the inverter assembly, making replacement more involved than a standalone sensor.
  • This code can be set by a poor ground connection that affects multiple sensors, so check ground points before replacing parts.
  • In some vehicles, the inverter temperature sensor shares a circuit with other sensors, and a fault in one can trigger multiple codes.
  • Always verify the sensor's resistance at the connector to rule out a wiring issue before condemning the inverter.

Can I keep driving with P0AF0?

Driving with P0AF0 is not recommended because the inverter may overheat and cause a sudden loss of power or hybrid system shutdown. Avoid driving until the fault is diagnosed and repaired, especially at high speeds or under heavy load.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage