Powertrain, generic · Hybrid propulsion

P0ACE Hybrid/EV Battery Temperature Sensor C Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0ACE flags erratic behaviour of battery temperature sensor C, meaning the reading jumps faster than the heavy battery mass could ever warm or cool. In GM's 2016 and 2019 hybrid tables the controller sums the absolute changes of the sensor value across a 10-sample window taken every 100 ms; a sum above 10 fails the window, and 4 failed windows out of 5 store the code as Type B, two trips. This is the same logic GM uses for sensors A and B. The older two-mode and 2013 programs do not list an erratic code for sensor C. Typical culprits are a loose terminal, a partly broken wire or a connector not fully latched after pack service. Several jumping sensors at once point to the sensing board.

Likely causes

Loose terminal or unlatched connector at sensor C
Partly broken sensor wire inside the pack
Fault on the battery sensing board affecting several inputs

Symptoms

  • Hybrid warning light that appears intermittently
  • Sensor C value jumps in live data
  • Occasional power limitation

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,000
Time1–5 h

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

Parts involved

hv battery temp sensor cwiring harnessbms

Related codes

P0ACAP0ACBP0ACCP0ACDP0AC9P0AEC

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