P00B4
Radiator Coolant Temperature Sensor Circuit High
Radiator coolant temperature sensor signal voltage above expected range. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.
Radiator coolant temperature sensor signal voltage above expected range. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.
Common causes
- high
Signal wire open
One of the most commonly reported causes for this code — check this first.
Typical part cost: $40-280
- low
Connector pins corroded - high contact resistance
Less common, but worth ruling out after the more likely causes.
Typical part cost: $40-280
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does P00B4 mean?
P00B4 means "Radiator Coolant Temperature Sensor Circuit High". It is a generic OBD-II code that points to a fault in the fuel & air metering / auxiliary emission controls.
What are the most common causes of P00B4?
signal wire open; connector pins corroded - high contact resistance; supply wire pinched against b+ source — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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