Powertrain, generic · Hybrid propulsion

P0ACC Hybrid/EV Battery Temperature Sensor C Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0ACC sets when the signal of battery temperature sensor C drops below the valid voltage window. For the NTC sensors GM uses, that equals an impossibly hot reading, most often caused by a short to ground in the pack wiring. GM's thresholds for sensor C mirror those for B: above 160 °C in 8 of 10 samples in the 2016 and 2019 tables, above 95 °C in 30 of 40 in the two-mode tables of 2011 and 2013, and below 0.3 V, about 90 °C, in 7 of 10 in the 2013 table 13OBDG05C; always Type B, two trips. Bulletin 18-NA-342 lists P0ACC for the Chevrolet Volt and prescribes a software update first. After that, inspect the sensor C wiring and the sensing board for chafing or moisture.

Likely causes

Sensor C signal shorted to ground
Thermistor shorted internally
Controller software setting the code falsely (Volt bulletin 18-NA-342)
Moisture at the sensing board connector

Symptoms

  • Check engine or hybrid warning light
  • Sensor C shows an implausibly high temperature
  • Reduced charging and electric drive power

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 cwiring harnessbms

Related codes

P0ACDP0ACAP0ACBP0AC7P0AEA

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.