Faulty coolant temperature sensor C itself, such as an open or shorted thermistor; Damaged or corroded wiring harness or connector at the sensor; Poor electrical connection at the control module pins; Coolant level low or air pockets causing inaccurate sensor readings; Failed control module driver circuit for the sensor; Aftermarket or incorrect sensor installed previously; Contamination or sludge on the sensor tip affecting response

DTC codes / P2Bxx · Hybrid propulsion / P2B24

P2B24Hybrid/EV Electronics Coolant Temperature Sensor C Circuit

Q: What does code P2B24 mean?

Hybrid/EV Electronics Coolant Temperature Sensor C Circuit. P2B24 indicates that the hybrid or electric vehicle's electronics coolant temperature sensor, specifically the 'C' circuit, is reporting a voltage or signal outside the expected range to the control module. The computer detects this when the sensor's output does not correlate with other temperature inputs or falls outside the normal operating window, often due to an open, short, or erratic connection.

P2B24 indicates that the hybrid or electric vehicle's electronics coolant temperature sensor, specifically the 'C' circuit, is reporting a voltage or signal outside the expected range to the control module. The computer detects this when the sensor's output does not correlate with other temperature inputs or falls outside the normal operating window, often due to an open, short, or erratic connection.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light or service vehicle soon message
Reduced hybrid system performance or entry into limp mode
Possible overheating warning if coolant temperature is actually high
Inconsistent or disabled cabin climate control
Often no symptoms besides the warning light, especially if the fault is intermittent
Fan running excessively or not at all due to lost temperature feedback

Common causes, most likely first

Faulty coolant temperature sensor C itself, such as an open or shorted thermistor
Damaged or corroded wiring harness or connector at the sensor
Poor electrical connection at the control module pins
Coolant level low or air pockets causing inaccurate sensor readings
Failed control module driver circuit for the sensor
Aftermarket or incorrect sensor installed previously
Contamination or sludge on the sensor tip affecting response

How to diagnose and fix it

Verify coolant level and condition, then pressure test the cooling system for leaks
Inspect the sensor connector and wiring for corrosion, chafing, or loose pins
Measure sensor resistance with a multimeter and compare to temperature-resistance chart
Backprobe the sensor signal circuit at the control module to check for voltage drop
Perform a wiggle test on the harness while monitoring live sensor data to catch intermittent faults
Replace the coolant temperature sensor C if resistance is out of specification
Clear codes and verify the repair with a road test and live data review

What the coolant sensor C circuit really tells you

A common misdiagnosis is replacing the sensor when the real fault is a chafed wire behind the engine block that only shorts when the engine moves under load.
The 'C' circuit designation often refers to a second or redundant sensor in a multi-sensor system, so a failure may not trigger an immediate overheat warning but can still degrade hybrid efficiency.
Low coolant or trapped air can cause the sensor to read a temperature that is plausible but wrong, setting the code without any physical sensor fault.
Some vehicles use the same sensor for both battery thermal management and cabin heating, so a fault can cause climate control symptoms that seem unrelated to the powertrain.
After a coolant flush, air pockets can cause a temporary P2B24 that clears after proper bleeding, so do not replace parts before verifying coolant fill and bleed procedure.

Can I keep driving with P2B24?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy loads, sustained high speeds, or towing because the hybrid system may not manage coolant temperature correctly. If the temperature gauge climbs or a red overheat warning appears, stop safely and shut off the vehicle.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.