P0AC7Hybrid/EV Battery Temperature Sensor B Circuit Low
- 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
- P0AC7 means the voltage of battery temperature sensor B is below its valid range. GM's sensors are NTC thermistors, so a low voltage equals an extremely hot reading, usually from a short to ground. The thresholds differ by program: the 2016 and 2019 tables fail it above 160 °C in 8 of 10 samples; the two-mode tables of 2011 and 2013 above 95 °C in 30 of 40 samples; GM's 2013 table 13OBDG05C below 0.3 V, about 90 °C, in 7 of 10. All are Type B, two trips. GM's Volt bulletin 18-NA-342 names P0AC7 among sensor codes that can set falsely and calls for a software update. A genuine hot pack would trip far lower thresholds first, so treat P0AC7 as an electrical fault.
- What you may notice
- Check engine or hybrid warning light
- Sensor B shows an implausibly high temperature
- Charging and drive power reduced
- Likely causes
- LikelySensor B signal shorted to ground inside the pack harness
- PossibleThermistor shorted internally
- RareController software setting the code falsely (Volt bulletin 18-NA-342)
- RareMoisture or coolant at the sensing board connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €60 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.