P2B27 code meaning
Hybrid/EV Electronics Coolant Temperature Sensor C Circuit High
Powertrain system Generic code P2Bxx codes Check engine light
What P2B27 means
P2B27 is logged when sensor C in the power electronics coolant loop sends a signal near the top of the reference, which the controller would have to read as deep frost. Far more often than real cold, the reason is a circuit that has opened: a connector that has backed out, a terminal pushed out of its cavity, a broken wire near a moving part or a failed element; shorting to the battery feed is rarer. No manufacturer documents P2B27 publicly; NTN-SNR names an excessive sensor C signal. As an order of magnitude, GM flags its sensor A above 98 % of the reference (P0CF1). CARB counts these sensors as monitored inverter cooling inputs. Unlike the low fault, a cold reading can hide real heat, so the controller usually switches to a substitute value and limits power. P2B26 is the grounded counterpart.
P2B27 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2B27
- Warning lamp and hybrid system message
- Sensor C shown far below outside temperature in live data
- Limited electric power
Common causes of P2B27
- Most likelyConnector backed out, terminal pushed out or wire broken
- PossibleSensor C element open
- Less likelySignal line shorted to battery voltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hybrid electronics coolant temp sensor cWiring harnessHybrid control module
What each part of P2B27 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| 27 | The exact fault in that area. |
What to do next
- Note P2B27 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 P2B27
What does P2B27 mean?
P2B27 means "Hybrid/EV Electronics Coolant Temperature Sensor C Circuit High". P2B27 is logged when sensor C in the power electronics coolant loop sends a signal near the top of the reference, which the controller would have to read as deep frost. It is a generic code, so it means the same on every make.
Is it safe to drive with P2B27?
Drive gently and only to a workshop. With P2B27 the car can go into limp mode (reduced power) to protect itself.
Will P2B27 fail an emissions test?
Yes, it can. P2B27 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 P2B27 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2B27 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.