P0CAC code meaning
Hybrid/EV Battery Temperature Sensor M Circuit Intermittent/Erratic
Powertrain system Generic code P0Cxx codes Check engine light
What P0CAC means
P0CAC catches a sensor M signal that jumps around without necessarily leaving its permitted band. GM's HPC2 tables (16OBDG02 to 19OBDG02) add up the absolute changes between successive samples over a ten-sample window at 100 ms; whenever that total passes 10 the window is marked bad, and four bad windows in five lead to a Type B code after two trips. The test runs with more than 10.2 V supply and needs a working link to the battery interface module. Since the value may stay within limits, the hard codes P0CAA and P0CAB can remain silent. Mitsubishi has no jitter code for its pack sensors. Fretting contacts, a cracked conductor on the board or vibration-sensitive wiring are the usual reasons; wiggle tests with live data and freeze-frame records help to localise the fault.
P0CAC 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 P0CAC
- Warning lamp that may go out again on its own
- Jumping sensor M value in live data
Common causes of P0CAC
- Most likelyFretting or loose contact in the sensor M circuit
- PossibleCracked conductor or solder joint on the monitoring board
- Less likelyUnstable ground of the 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 P0CAC 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. |
| AC | The exact fault in that area. |
What to do next
- Note P0CAC 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 P0CAC
What does P0CAC mean?
P0CAC means "Hybrid/EV Battery Temperature Sensor M Circuit Intermittent/Erratic". P0CAC catches a sensor M signal that jumps around without necessarily leaving its permitted band. It is a generic code, so it means the same on every make.
Is it safe to drive with P0CAC?
Drive gently and only to a workshop. With P0CAC the car can go into limp mode (reduced power) to protect itself.
Will P0CAC fail an emissions test?
Yes, it can. P0CAC 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 P0CAC to fix?
Difficulty: workshop only. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P0CAC 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.