High Speed Radiator Fan Ground Control Relay Circuit (Chrysler)
What does P1498 mean?
The P1498 code means the vehicle's onboard diagnostic system has detected: High Speed Radiator Fan Ground Control Relay Circuit (Chrysler). This is a critical severity code.
Common Symptoms
- Cooling fan does not operate at high speed
- Engine overheating in slow traffic or hot weather
- Check Engine Light illuminated
- AC performance degrades at low vehicle speeds
- Temperature gauge climbs above normal operating range
Probable Causes (Ranked by Likelihood)
- Failed high-speed fan ground control relay Very High
- Poor ground connection at the fan relay or motor High
- Corroded relay socket Moderate
- Open wiring in the fan ground circuit Moderate
- PCM ground control driver failure Low
Step-by-Step Diagnostic Procedure
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Locate the high-speed fan ground control relay and swap with a matching relay to test.
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Check the ground connections for the relay and fan motor with a voltage drop test.
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Inspect the relay socket for heat damage, corrosion, or melted plastic.
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Measure the PCM ground control signal at the relay when high speed is commanded.
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Test the wiring between the relay ground control terminal and the PCM.
Frequently Asked Questions
What is a ground control relay?
Instead of switching the power side, a ground control relay is activated when the PCM provides a ground signal to the relay coil. This is the most common relay control method used by Chrysler.
How do I test for a bad ground?
Perform a voltage drop test on the ground circuit. With the fan running (or relay energized), measure voltage across the ground wire. More than 0.2V indicates a poor ground connection.
Can I drive safely with only low-speed fan?
For short highway drives, yes. Avoid stop-and-go traffic, towing, and idling for extended periods. The low-speed fan may not provide sufficient cooling under heavy thermal loads.