P0C34: 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. 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.

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

MIL on after two trips
Battery too cold or reduced power message
Limited charge and discharge power

Most likely causes

Sensor F drifting or poorly seated on its cell group
Module software setting the code falsely in the cold (GM Volt)
Real local temperature difference from a weak cell group or uneven cooling

What to check, in order

Start with the simplest. You can tick off each step.

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Compare the reading with other engine data while varying the engine speed.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

It can trigger limp mode.
It affects emissions.

What each character of P0C34 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
C: Subsystem depends on the code range
34: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0C34?

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 P0C34?

The most common causes are: sensor F drifting or poorly seated on its cell group; module software setting the code falsely in the cold (GM Volt); real local temperature difference from a weak cell group or uneven cooling.

Related codes

Sources

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.