P0C9BHybrid/EV Battery Temperature Sensor L 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
- P0C9B covers a sensor L signal that jitters. GM's tables 18OBDG02 and 19OBDG02 integrate the absolute sample-to-sample changes over ten readings spaced 100 ms apart; when the integral exceeds 10, that window fails, and 4 failures within 5 windows store the code, classed Type B. Supply must exceed 10.2 V and communication with the battery interface module must be present. Because the value may never leave its valid band, P0C99 and P0C9A can stay silent. Mitsubishi does not use this code. A fretting pin, a cracked conductor or a loose board ground are typical, and the fault may vanish between drives, so freeze-frame data and a wiggle test help to find it.
- What you may notice
- Warning lamp that may switch off again by itself
- Erratic sensor L value in live data
- Likely causes
- LikelyFretting pin in the sensor L connector
- PossibleCracked conductor in the sensor L lead
- RareLoose ground on the cell monitoring 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.