P0C85Hybrid/EV Battery Temperature Sensor H Circuit Intermittent/Erratic
- 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
- P0C85 points to a sensor H reading that flickers. A battery pack warms and cools slowly, so fast swings in one channel suggest an electrical contact problem rather than real heat. GM's 2018 hybrid table 18OBDG02 adds up how much the value moves within a 10-sample window at 100 ms per sample; once that sum passes 10 in 4 of 5 evaluations, the module logs P0C85, Type B over two trips, as long as the supply exceeds 10.2 V and the battery interface module is talking. The 2019 table 19OBDG02 keeps the same rule. GM's OBDG01 tables of 2011 to 2016 (first-generation Volt, ELR) and Mitsubishi list no such code for sensor H. A wiggle test on the harness while watching live data usually finds the fault; low or high voltage faults are P0C83 and P0C84 instead.
- What you may notice
- Intermittent warning lamp
- Sensor H value jumping in live data
- Likely causes
- LikelyIntermittent contact at the sensor H terminal
- PossiblePartly broken sensor H wire inside the pack harness
- RareNoisy 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: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.