Radiator Coolant Temperature Sensor
Measures coolant leaving the radiator, as distinct from the engine coolant temperature sensor which measures coolant leaving the engine. The difference between the two is the point of fitting it — it tells the module how much heat the radiator is actually removing, which is a measurement no single sensor can make.
That comparison catches faults that have no sensor of their own. A thermostat stuck open, a radiator blocked internally or externally, a cooling fan that never runs, and an airlock all show as the wrong temperature difference across the radiator. It also lets the module run the fan and the thermostat to a target rather than a threshold, which is how modern engines hold a deliberately high running temperature for efficiency and drop it under load.
Its range/performance faults have two very different meanings and the cheap test separates them: after a night standing, this sensor must read close to ambient and close to the engine sensor. Disagreement then is a drifted sensor; agreement cold with the wrong difference running means the cooling system is genuinely at fault — which is much more serious and is exactly what this sensor exists to catch.
Also known as: radiator outlet temperature sensor, radiator temp sensor, coolant outlet sensor, low temperature radiator sensor
Referenced by 11 codes
Codes involving this component (11)
- P00B2 Radiator Coolant Temperature Sensor Circuit Range/Performance Moderate
- P00B1 Radiator Coolant Temperature Sensor Circuit
- P00B3 Radiator Coolant Temperature Sensor Circuit Low
- P00B4 Radiator Coolant Temperature Sensor Circuit High
- P00B5 Radiator Coolant Temperature Sensor Circuit Intermittent/Erratic
- P00B6 Radiator Coolant Temperature/Engine Coolant Temperature Correlation
- P00DE Charge Air Cooler Coolant Temperature Sensor A Circuit
- P00DF Charge Air Cooler Coolant Temperature Sensor A Circuit Range/Performance
- P00E0 Charge Air Cooler Coolant Temperature Sensor A Circuit Low
- P00E1 Charge Air Cooler Coolant Temperature Sensor A Circuit High
- P00E2 Charge Air Cooler Coolant Temperature Sensor A Intermittent/Erratic
Other components in Cooling
- Electric Coolant Pump 149
- Engine Coolant Temperature Sensor 105
- Engine Coolant Flow Control Valve 82
- Radiator 61
- Active Grille Shutter Module 53
- Engine Coolant Bypass Valve 42
- Thermostat 40
- Cooling Fan 40
- Engine Coolant Level Sensor 15
- Water Pump 12
- Coolant Expansion Tank 8
- Fuel Fired Heater 5
- Coolant Degassing Valve 3
- Oil Cooler 1
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