P0AAFHybrid/EV Battery Pack Air Temperature Sensor A Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Air temperature sensor A is the thermistor GM places at the cooling air inlet of air-cooled hybrid packs. Being an NTC type, a high signal voltage means the controller sees implausibly cold air, typically from an open wire or a lost ground. GM's 2013 table 13OBDG05C sets P0AAF above 4.63 V, equal to about -45 °C, in 7 of 10 samples; the two-mode hybrid tables of 2011 and 2013 use a reading below -45 °C in 30 of 40 samples. All are Type B, two trips. The controller then ignores the inlet value, so fan control and the inlet-to-outlet comparison lose their reference. Check the connector at the inlet duct for a pushed-out pin first. The shorted counterpart reading as very hot is P0AAE.
- What you may notice
- Check engine or hybrid warning light
- Scan tool shows inlet air near -40 °C regardless of weather
- Battery fan runs on a fixed default speed
- Likely causes
- LikelyOpen signal or ground wire between sensor and battery controller
- PossibleConnector at the air inlet duct loose or with pushed-back pin
- PossibleThermistor open internally
- RareBattery controller input fault
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.