P0C34 code meaning
Hybrid/EV Battery Temperature Sensor F Circuit Range/Performance
Powertrain system Generic code P0Cxx codes Check engine light
What P0C34 means
P0C34 checks whether sensor F, GM's sensor 6, agrees with the rest of the pack. The controller compares its reading with the average of the other battery temperature sensors. GM's 2016 hybrid table fails it above 25 °C difference in 50 of 67 samples; the Volt and plug-in tables of 2016 to 2019 use 20 °C, in 2018 for 5 s within 6.7 s; the air-cooled eAssist (13OBDG05C) allows only 8.55 °C and tests only after more than six hours with the module off. All are Type B, two trips. Active circuit codes suspend the test, so P0C34 means a sensor that reads wrongly but within range, or a real local hot or cold spot. Volt bulletin 18-NA-342 names it sensor 6 performance among codes that set in cold weather without a hardware fault.
P0C34 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0C34
- MIL on after two trips
- Battery too cold or reduced power message
- Limited charge and discharge power
Common causes of P0C34
- PossibleSensor F drifting or poorly seated on its cell group
- PossibleModule software setting the code falsely in the cold (GM Volt)
- Less likelyReal local temperature difference from a weak cell group or uneven cooling
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery temp sensor fWiring harnessBms
What each part of P0C34 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C | Area: hybrid propulsion. |
| 34 | The exact fault in that area. |
What to do next
- Note P0C34 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0C34
What does P0C34 mean?
P0C34 means "Hybrid/EV Battery Temperature Sensor F Circuit Range/Performance". P0C34 checks whether sensor F, GM's sensor 6, agrees with the rest of the pack. It is a generic code, so it means the same on every make.
Is it safe to drive with P0C34?
Drive gently and only to a workshop. With P0C34 the car can go into limp mode (reduced power) to protect itself.
Will P0C34 fail an emissions test?
Yes, it can. P0C34 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0C34 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will P0C34 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.