P0BC4 code meaning
Hybrid/EV Battery Temperature Sensor E Circuit Low
Powertrain system Generic code P0Bxx codes Check engine light
What P0BC4 means
Sensor E is an NTC thermistor with a pull-up resistor, so its voltage falls as it gets hotter; a short to ground therefore looks like an extremely hot cell group. GM's 2016 table sets P0BC4 when the converted value exceeds 160 °C in 8 of 10 samples; the 2011 Volt table and GM's 2019 battery module table use above 87.5 °C for 1.4 s within 2 s; the eAssist mild hybrid flags a sense voltage under 0.3 V, about 90 °C, in 7 of 10 samples. All are Type B, two trips. Volt bulletin 18-NA-342 names it sensor 5 circuit low voltage. Its counterpart is P0BC5 (open circuit, reads very cold); a genuinely overheated pack is reported as P0A7E. Because the controller must assume heat, it cuts charge and discharge power and may run cooling at full speed.
P0BC4 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 P0BC4
- MIL on after two trips
- Implausibly high temperature for sensor E on the scan tool
- Reduced power and battery fan or cooling at full speed
Common causes of P0BC4
- Most likelySensor E signal wire shorted to ground inside the pack
- PossibleInternally shorted thermistor E
- Less likelyMoisture or contamination on the sensing board
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 eWiring harnessBms
What each part of P0BC4 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B | Area: hybrid propulsion. |
| C4 | The exact fault in that area. |
What to do next
- Note P0BC4 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 P0BC4
What does P0BC4 mean?
P0BC4 means "Hybrid/EV Battery Temperature Sensor E Circuit Low". Sensor E is an NTC thermistor with a pull-up resistor, so its voltage falls as it gets hotter; a short to ground therefore looks like an extremely hot cell group. It is a generic code, so it means the same on every make.
Is it safe to drive with P0BC4?
Drive gently and only to a workshop. With P0BC4 the car can go into limp mode (reduced power) to protect itself.
Will P0BC4 fail an emissions test?
Yes, it can. P0BC4 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 P0BC4 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will P0BC4 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.