Powertrain, generic · Hybrid propulsion

P0C7C Hybrid/EV Battery Temperature Sensor G Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

P0C7C is the umbrella circuit code for battery temperature sensor G, used when the controller sees an electrical fault in that input without sorting it into low, high or erratic. No manufacturer documents P0C7C publicly. GM numbers sensor G as sensor 7 of the nine thermistors in the Volt pack (bulletin 18-NA-342), yet its hybrid tables only carry the narrower codes P0C7D to P0C80; Mitsubishi likewise splits sensor G into rationality, short and open. CARB section (e)(15.3.1) asks for continuous checks of range and circuit continuity on every such input. Without a trustworthy reading the battery controller has to assume the worst for that cell group and trims charge and discharge power. The thermistor lives inside the high-voltage pack, so testing needs HV safety procedures.

Likely causes

Corroded or loose connector between sensor G and the sensing board

Thermistor G failed electrically

Faulty input stage on the cell monitoring board or battery module

Symptoms

Hybrid or EV system warning lamp, check-engine lamp on many models
Reduced electric power and slower charging
Battery cooling or heating running without obvious need

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 gwiring harnessbms

References: law.cornell.edu, static.nhtsa.gov, gsi.ext.gm.com.