Radiator Coolant Temperature Sensor Circuit Range/Performance
What it means
P00B2 means the radiator coolant temperature sensor is giving a reading that's out of its normal range or doesn't track how the engine actually warms and cools. This sensor — separate from the main engine coolant sensor — helps the ECM control the radiator cooling fans. A faulty reading can leave the fans running too much or too little, so overheating is possible if it's ignored.
Can I keep driving? Cautiously — this sensor helps manage the cooling fans, so a bad reading can let the engine run hotter than it should; watch the temperature gauge and avoid hard driving until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Cooling fans running constantly, or not coming on when they should
- Engine temperature higher than normal, or slow to reach operating temp
- Possible overheating in traffic or on hot days
Common causes
Most likely first
- Faulty or lazy radiator coolant temperature sensorLikely
- Low coolant level or a stuck thermostat producing an abnormal temperature the sensor reportsCommon
- Corroded/loose connector or damaged wiring at the sensorCommon
- Cooling-fan or fan-relay faultLess often
- Rarely, an ECM faultLess often
How to diagnose & fix
Work through it in order
- Check coolant level and condition first; top up and bleed air if low.
- Read live data and compare the radiator sensor's temperature to the engine coolant sensor — they should track closely once warm.
- Inspect the sensor's connector and wiring for corrosion or damage.
- Replace the radiator coolant temperature sensor if its reading stays out of range.
- Verify cooling-fan operation; clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P00B2?+
Can I just clear P00B2?+
Related codes
Often seen with P00B2
Read & clear P00B2 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.