P0CA9Hybrid/EV Battery Temperature Sensor M Circuit Range/Performance
- 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
- P0CA9 reports that sensor M stays within its electrical limits yet disagrees with what the remaining pack sensors measure. GM's 2012 Volt table 12OBDG01A only runs the comparison once drive system, plug-in charging and battery conditioning have rested for over 21,600 s; a spread above 25.3 °C from the mean in 50 of 67 samples is a Type B failure. The 2018 HPC2 table 18OBDG02 uses 25.00 °C at 25 ms sampling and is suspended whenever circuit faults of the sensors or a communication loss with the battery interface module exist. Mitsubishi uses P0CA9 for module sensor [12] of the Outlander PHEV: after more than 3,600 s soak and at pack temperatures from −30 to 60 °C, a deviation of 13 °C or more from the mean of all 50 sensors for 0.32 s sets it. Drift or a loose sensor is typical.
- What you may notice
- Warning lamp appearing after a long parking period
- Battery power limited
- Likely causes
- LikelyThermistor M drifting while staying in its electrical range
- PossibleSensor M lost thermal contact with its module
- RareModule section genuinely warmer or colder, e.g. cooling fault or weak cell
- 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: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.