P0BC4Hybrid/EV Battery Temperature Sensor E Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- 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
- Likely causes
- LikelySensor E signal wire shorted to ground inside the pack
- PossibleInternally shorted thermistor E
- RareMoisture or contamination on the sensing board
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €60 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.