What Does P1484 Mean?
The primary cooling fan control circuit has a malfunction preventing proper high-speed fan operation. This can be due to a faulty fan relay, damaged wiring, or a problem with the PCM driver circuit.
Common Causes
40%
Failed high-speed cooling fan relay
25%
Damaged wiring or poor connection in fan control circuit
20%
Failed cooling fan motor with high resistance
10%
Blown fuse or fusible link in fan circuit
5%
PCM driver circuit failure
Diagnostic Steps
1
Step 1: Check cooling fan fuses and relays; swap relay with identical relay to test
2
Step 2: Command fan on high speed using scan tool active test; monitor fan operation
3
Step 3: Check voltage at fan motor during high-speed command; should be battery voltage
4
Step 4: Test fan relay coil control circuit from PCM for proper ground signal
5
Step 5: If relay and power circuits test good, check fan motor current draw and resistance
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
The primary cooling fan control circuit has a malfunction preventing proper high-speed fan operation. This can be due to a faulty fan relay, damaged wiring, or a problem with the PCM driver circuit.
The most common cause of P1484 (High Fan Control Primary Circuit Malfunction) is: Failed high-speed cooling fan relay
Typical repair costs for P1484 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine may overheat in stop-and-go traffic or hot weather conditions. Monitor temperature gauge closely and avoid prolonged idling until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1484 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Cooling System
Difficulty
Type
Manufacturer
Recommended Tools
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