P0C42 code meaning
Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit
Powertrain system Generic code P0Cxx codes Check engine light
What P0C42 means
P0C42 is the general circuit code for the first coolant temperature sensor in the liquid loop of a hybrid or EV battery, typically placed at the pack inlet. The battery controller uses it to decide when to pump, heat or chill the coolant. Volvo documents P0C4200 in the battery energy control module of the XC90 T8 plug-in hybrid from model year 2016, as either an intermittent or a permanent entry with a possible check engine lamp; according to technical journal TJ 33546, once the current software is verified the entry is simply erased and no parts are needed. GM reports faults of the same sensor more precisely as P0C44 and P0C45. CARB requires the inputs of the battery thermal management to be monitored. P0C43 covers implausible readings, P0CD5 sensor B.
P0C42 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0C42
- Check engine lamp, often without other complaints
- Battery cooling or heating running on substitute values
- Reduced charging or drive power in hot or cold weather
Common causes of P0C42
- Most likelyBattery controller software flagging the circuit wrongly (Volvo XC90 T8)
- PossibleCorroded or loose connector or damaged wire at the coolant sensor
- Less likelyFailed coolant temperature sensor A
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery pack coolant temp sensor aWiring harnessBms
What each part of P0C42 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. |
| 42 | The exact fault in that area. |
What to do next
- Note P0C42 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 P0C42
What does P0C42 mean?
P0C42 means "Hybrid/EV Battery Pack Coolant Temperature Sensor A Circuit". P0C42 is the general circuit code for the first coolant temperature sensor in the liquid loop of a hybrid or EV battery, typically placed at the pack inlet. It is a generic code, so it means the same on every make.
Is it safe to drive with P0C42?
Drive gently and only to a workshop. With P0C42 the car can go into limp mode (reduced power) to protect itself.
Will P0C42 fail an emissions test?
Yes, it can. P0C42 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 P0C42 to fix?
Difficulty: hard. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P0C42 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.