P0CA8 code meaning
Hybrid/EV Battery Temperature Sensor M Circuit
Powertrain system Generic code P0Cxx codes Check engine light
What P0CA8 means
P0CA8 is the general circuit code for battery temperature sensor M, meant for electrical faults that the controller does not sort into low, high or erratic. No manufacturer publishes this exact code. In GM's 2011 Volt table the rationality list gives M the thirteenth of sixteen positions, yet GM only defines P0CA9 to P0CAC for it. Mitsubishi's Outlander PHEV assigns M to module sensor [12] and also uses only the rationality, short and open codes. CARB section (e)(15.3.1) requires continuous checks of range and continuity for inputs of this kind. Without a usable value the battery controller must assume a hot module section and restricts power. Repair means opening the made-safe traction battery and checking the sensor, its leads and the plug at the monitoring board.
P0CA8 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0CA8
- Hybrid or EV warning, possibly with check-engine lamp
- Electric power reduced until repaired
Common causes of P0CA8
- Most likelyPoor contact at the plug of sensor M on the monitoring board
- PossibleThermistor M damaged
- Less likelyFaulty input channel of the cell monitoring board
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery temp sensor mWiring harnessBms
What each part of P0CA8 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C | Area: hybrid propulsion. |
| A8 | The exact fault in that area. |
What to do next
- Note P0CA8 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0CA8
What does P0CA8 mean?
P0CA8 means "Hybrid/EV Battery Temperature Sensor M Circuit". P0CA8 is the general circuit code for battery temperature sensor M, meant for electrical faults that the controller does not sort into low, high or erratic. It is a generic code, so it means the same on every make.
Is it safe to drive with P0CA8?
Drive gently and only to a workshop. With P0CA8 the car can go into limp mode (reduced power) to protect itself.
Will P0CA8 fail an emissions test?
Yes, it can. P0CA8 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0CA8 to fix?
Difficulty: workshop only. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P0CA8 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.