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.
High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
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
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P0C7C means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- C: Subsystem depends on the code range
- 7C: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0C7C?
If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
What causes code P0C7C?
The most common causes are: 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.
Related codes
- P0C7DHybrid/EV Battery Temperature Sensor G Circuit Range/Performance
- P0C7EHybrid/EV Battery Temperature Sensor G Circuit Low
- P0C7FHybrid/EV Battery Temperature Sensor G Circuit High
- P0C80Hybrid/EV Battery Temperature Sensor G Circuit Intermittent/Erratic
- P0C33Hybrid/EV Battery Temperature Sensor F Circuit
- P0C81Hybrid/EV Battery Temperature Sensor H Circuit
- P0C86Hybrid/EV Battery Temperature Sensor F/G Correlation
Sources
- law.cornell.edu: 13 CCR 1968.2
- static.nhtsa.gov: MC 10155116 9999
- gsi.ext.gm.com: 19OBDG02 Hybrid Diagnostics
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.