Radiator Temperature Sensor Circuit High (Chrysler)
What does P1198 mean?
The P1198 code means the vehicle's onboard diagnostic system has detected: Radiator Temperature Sensor Circuit High (Chrysler). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Temperature gauge reading abnormally low
- Cooling fans may run continuously
- Extended warm-up fuel enrichment
- Poor fuel economy
Probable Causes (Ranked by Likelihood)
- Failed radiator temperature sensor (open circuit) Very High
- Open wiring in sensor circuit High
- Disconnected sensor connector Moderate
- Corroded sensor ground connection Moderate
- PCM input circuit failure Low
Step-by-Step Diagnostic Procedure
-
Read the radiator temperature sensor value on a scan tool
-
Inspect the sensor connector at the radiator for a secure connection
-
Measure sensor resistance with a multimeter (should vary with temperature)
-
Check wiring continuity from sensor to PCM
-
Replace the sensor if it reads open or out of specification
Frequently Asked Questions
What is the radiator temperature sensor?
On Chrysler vehicles, the radiator temperature sensor is separate from the engine coolant temperature sensor. It measures the temperature of coolant exiting the radiator to help the PCM manage cooling fan operation.
Why are the cooling fans running constantly with P1198?
When the sensor reads high voltage (open circuit), the PCM assumes the sensor has failed and runs the cooling fans as a precaution to prevent overheating. This is a safety measure built into the system.
Where is the radiator temperature sensor located?
On most Chrysler vehicles, the radiator temperature sensor is located in the lower radiator tank or the lower radiator hose. It is accessible from under the vehicle or from the front of the engine bay.