P0CB9 code meaning
Hybrid/EV Battery Temperature Sensor P Circuit Low
Powertrain system Generic code P0Cxx codes Check engine light
What P0CB9 means
P0CB9 means the voltage of sensor P has fallen under the valid range. As with the other NTC sensors, low voltage corresponds to high temperature, so a short to ground or a collapsed thermistor makes the module appear to be glowing hot. In GM's HPC2 tables 18OBDG02 and 19OBDG02 the code is set after 8 of 10 readings above 160 °C at 100 ms spacing, Type B, two trips, once system voltage exceeds 10.2 V and the battery interface module communicates. The 2011 Volt table already contained it with 87.5 °C, a raw count below 680, held 1.4 s within 2 s. Mitsubishi treats P0CB9 as a short of module sensor [15] of the Outlander PHEV, below 0.12 V for 2 s, lists no fail-safe function and names battery module or cell monitoring unit as the parts to replace. A genuinely hot pack is reported by P0A7E.
P0CB9 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 P0CB9
- Module P shown as extremely hot in live data
- Severe power limitation with warning lamp
Common causes of P0CB9
- Most likelySensor P signal shorted to ground
- PossibleThermistor P internally shorted
- Less likelyDamaged input of the cell monitoring unit for sensor P
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 pWiring harnessBms
What each part of P0CB9 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. |
| B9 | The exact fault in that area. |
What to do next
- Note P0CB9 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 P0CB9
What does P0CB9 mean?
P0CB9 means "Hybrid/EV Battery Temperature Sensor P Circuit Low". P0CB9 means the voltage of sensor P has fallen under the valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with P0CB9?
Drive gently and only to a workshop. With P0CB9 the car can go into limp mode (reduced power) to protect itself.
Will P0CB9 fail an emissions test?
Yes, it can. P0CB9 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 P0CB9 to fix?
Difficulty: workshop only. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P0CB9 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.