P0C81Hybrid/EV Battery Temperature Sensor H Circuit
- 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
- P0C81 reports an electrical fault on the input of battery temperature sensor H that the controller does not narrow down further. No manufacturer documents this exact code publicly. In GM's Volt pack sensor H is sensor 8 (bulletin 18-NA-342), and both the 2016 Cadillac ELR table (16OBDG01) and the later Volt tables list only the specific H codes P0C82 to P0C85. Regulators still expect the input to be watched: CARB section (e)(15.3.1) requires continuous monitoring of value range and circuit continuity for such sensors. If the controller cannot trust H it treats the affected cell group as at risk and limits battery power until the fault clears. A generic circuit code calls for a full check of the wiring and connector from the thermistor to the sensing board, inside the HV pack.
- What you may notice
- Hybrid or EV warning lamp
- Limited acceleration in electric mode
- Charging slower than usual
- Likely causes
- LikelyPoor contact at the sensor H connector
- PossibleThermistor H defective
- RareDamaged measuring channel 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: €150 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.