Code Definition

P1198 — Radiator Temperature Sensor input voltage too high

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Chrysler

About P1198

P1198 is a manufacturer-specific powertrain diagnostic trouble code recorded for Chrysler vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1198 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.

P1198 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

On Chrysler vehicles, P1198 sets when the PCM sees the radiator temperature sensor signal voltage rise above its calibrated maximum, which corresponds to an unrealistically cold reading and usually means an open circuit or a failed sensor. The radiator temperature sensor is a negative temperature coefficient thermistor, so its resistance falls as temperature rises and climbs as it cools, and the PCM reads the resulting voltage on a 5V reference circuit. The PCM uses this input, often alongside the engine coolant temperature sensor, to manage the cooling fans and thermal strategy. When the sign...

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