Code Definition

P00B4 — Radiator Temperature Sensor Signal High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P00B4

P00B4 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P00B4 is stored, the module has detected a signal or supply voltage higher than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P00B4 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The fault code P00B4 is set when the Engine Control Module (ECM) identifies that the signal from the radiator temperature sensor is higher than the normal operational range. This high signal can indicate a sensor fault or a circuit problem, such as a short to voltage. It can also suggest the actual coolant temperature is excessively high, although this is less common if the engine is not overheating. The ECM uses the radiator temperature sensor to gauge the coolant temperature, and a high signal might lead to incorrect cooling strategies or engine management decisions.

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