Fan Secondary High Speed Circuit Malfunction (Ford)
What does P1474 mean?
The P1474 code means the vehicle's onboard diagnostic system has detected: Fan Secondary High Speed Circuit Malfunction (Ford). This is a critical severity code.
Common Symptoms
- Engine overheating under load or in traffic
- Cooling fan does not reach high speed
- Check Engine Light illuminated
- AC system shuts down at high temperatures
- Coolant may boil over in severe cases
Probable Causes (Ranked by Likelihood)
- Failed high-speed fan relay Very High
- Blown cooling fan fuse for high speed High
- Faulty cooling fan motor (high-speed winding) High
- Damaged wiring in the high-speed fan circuit Moderate
- PCM output driver failure for high-speed command Low
Step-by-Step Diagnostic Procedure
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Check the high-speed fan relay and its fuse. Swap with a known good relay and test.
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Apply 12V directly to the fan motor high-speed terminal to verify the motor works.
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Use a scan tool to command high-speed fan operation and check for PCM signal at the relay connector.
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Inspect the wiring from the relay to the fan motor for chafing, melted insulation, or breaks.
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Check the fan motor ground connection for corrosion or high resistance.
Frequently Asked Questions
Is P1474 more serious than P1473?
Yes. The high-speed fan circuit is the last line of defense against overheating. Without it, the engine can reach dangerous temperatures in traffic or under heavy load, potentially causing head gasket or engine damage.
What temperature triggers the high-speed fan?
On most Ford vehicles, the high-speed fan engages when coolant temperature reaches approximately 220 to 230 degrees Fahrenheit, or whenever the AC system is under high load.
Can a bad fan motor cause both P1473 and P1474?
Yes. If the fan motor itself has failed internally, both the low-speed and high-speed circuits will not function. Testing the motor directly with 12V will confirm if the motor is the root cause.