Powertrain, generic · Hybrid propulsion

P0AC6 Hybrid/EV Battery Temperature Sensor B Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0AC6 is the plausibility test for battery temperature sensor B: its reading is compared with the other pack sensors. GM documents several calibrations. The 2016 and 2019 tables fail it when the sensor differs from the average of the other sensors by more than 25 °C, 50 of 67 samples; the two-mode hybrid tables of 2011 and 2013 use more than 15 °C, 90 of 100 samples; GM's 2013 table 13OBDG05C allows 8.55 °C after more than 6 hours off. All are Type B, two trips. Bulletin 18-NA-342 for the Chevrolet Volt lists P0AC6 among false sensor codes in cold weather and fixes them by reprogramming. Otherwise a drifting sensor or a real local hot spot in a module is likely.

Likely causes

Sensor B drifted from its characteristic
Controller software flags the sensor falsely (GM Volt bulletin 18-NA-342)
Corroded contact adding resistance in the sensor circuit
Real temperature difference from a weak cell or blocked cooling

Symptoms

  • Check engine or hybrid warning light
  • One sensor reading far off the others in live data
  • Battery too cold message on the Volt in mild weather

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–2,500
Time0.5–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hv battery temp sensor bwiring harnessbms

Related codes

P0AC5P0AC7P0AC8P0AC9P0A9CP0ACB

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.