Powertrain, generic · Hybrid propulsion

P0BC2 Hybrid/EV Battery Temperature Sensor E Circuit

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

Battery temperature sensor E is the fifth thermistor in the high-voltage pack; GM's Chevrolet Volt bulletin 18-NA-342 lists the E codes as temperature sensor 5 of nine. P0BC2 is the general circuit code, used when the controller detects an electrical fault without classing it as low, high or erratic. GM's hybrid tables report only the specific siblings P0BC3 to P0BC6. NHTSA's summary of an Audi pending service solution for 2027 Q6 and A6 e-tron models names P0BC2 with a failure type byte among implausible temperature sensor errors. CARB requires battery temperature sensors to be monitored for circuit faults. With one value missing the controller limits charge and discharge power. The sensor sits inside the pack, so checks call for high-voltage safety procedures.

Likely causes

Loose or corroded connector of sensor E at the sensing board

Failed thermistor E

Faulty input on the battery sensing board or module

Symptoms

Hybrid or EV system warning and MIL
Reduced power or charging rate
Battery cooling running more than usual

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 ewiring harnessbms

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