Powertrain, generic · Hybrid propulsion

P0C8A Hybrid/EV Battery Temperature Sensor I Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0C8A records a sensor I voltage below the valid band. As the element is an NTC thermistor fed through a pull-up, a low voltage translates into a cell group that seems dangerously hot, typically caused by a short to ground. GM's 2012 Volt table (12OBDG01A) trips above 87.5 °C, an ADC count under 680, for 1.4 s within 2 s, two trips; the 2019 table 19OBDG02 instead fails above 160 °C in 8 of 10 samples, Type B. Bulletin 18-NA-342 assigns it to sensor 9 as the low-voltage fault. Mitsubishi's 2022 Outlander PHEV records a short of channel [08] under 0.12 V, above 125 °C, after 2 s and names the battery module or cell monitoring unit as the part to replace. P0C8B covers the open circuit, P0A7E a pack that really overheats.

Likely causes

Sensor I signal shorted to ground
Thermistor I shorted, for example after coolant or moisture entry
Cell monitoring unit input for sensor I faulty

Symptoms

  • Warning lamp with reduced power
  • Sensor I shown extremely hot in live data
  • Battery cooling running continuously

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–2,500
Time1–5 h

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

Parts involved

hv battery temp sensor iwiring harnessbms

Related codes

P0C8BP0C89P0C88P0C8CP0A7EP0C83

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