P0AF4 code meaning
Drive Motor Inverter Temperature Sensor B Circuit Low
Powertrain system Generic code P0Axx codes Check engine light
What P0AF4 means
P0AF4 reports a signal of inverter temperature sensor B below the valid range. GM uses an NTC thermistor with a pull-up, so a low voltage reads as an inverter far hotter than possible, usually from a short to ground or an internal sensor fault in the motor B inverter. GM's thresholds: above 170 °C for 2.5 of 3.5 s, Type B, two trips, in the 2016 to 2019 hybrid tables; above 159 °C, Type A, one trip, in another 2019 table; above 130 °C, Type A, on the 2011 Volt; above 125 °C, Type B, on the 2011 and 2013 two-mode trucks. A genuine overheat is reported separately as an over-temperature code such as P0A3D or P0C14. Because the sensor sits inside the inverter, the fix is usually the inverter assembly.
P0AF4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0AF4
- Malfunction indicator lamp and hybrid warning
- Motor B power strongly limited
- Reduced hybrid assist and regeneration
Common causes of P0AF4
- Most likelyShorted sensor or circuit inside the power inverter module
- PossibleSensor signal shorted to ground in external wiring, where present
- Less likelyMoisture or coolant inside the inverter housing
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Drive motor inverter temp sensor bHybrid control moduleWiring harness
What each part of P0AF4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| F4 | The exact fault in that area. |
What to do next
- Note P0AF4 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0AF4
What does P0AF4 mean?
P0AF4 means "Drive Motor Inverter Temperature Sensor B Circuit Low". P0AF4 reports a signal of inverter temperature sensor B below the valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with P0AF4?
Drive gently and only to a workshop. With P0AF4 the car can go into limp mode (reduced power) to protect itself.
Will P0AF4 fail an emissions test?
Yes, it can. P0AF4 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0AF4 to fix?
Difficulty: workshop only. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P0AF4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.