Powertrain, generic · Hybrid propulsion

P0C34 Hybrid/EV Battery Temperature Sensor F Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

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.

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

Symptoms

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

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€60–2,500

Time0.5–5 h

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

Parts involved

hv battery temp sensor fwiring harnessbms

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