P1477: Passenger Side Cooling Fan Fault
The P1477 code indicates that the Powertrain Control Module (PCM) has detected a malfunction in the electrodrive fan 2, located on the passenger side. This fan is part of the auxiliary cooling system and is responsible for forcing airflow through the radiator and/or A/C condenser when required by temperature, engine load, or A/C demand. The fault is logged when the fan fails to respond to the PCM activation signal, does not reach the commanded speed, or when there is an anomaly in the feedback from the fan motor control circuit.
01. Most Common Causes
- Defective, seized, or internally worn passenger side fan motor
- Failed relay, control module, or resistor for the auxiliary fan
- Open circuit, short to ground, or short to power in the fan 2 wiring or connectors
- Blown fuse in the secondary fan power supply circuit
- Poor, loose, or corroded ground connection at the fan motor
- Internal PCM failure in the fan control circuit (rare)
02. Symptoms You Will Notice
- Engine overheating, especially in traffic or at idle
- A/C performance reduced or warm air at idle
- Check Engine Light illuminated
- Cooling fan not running when it should
- Fan running continuously or at wrong speed
03. Step-by-Step Diagnosis
Scan for codes and verify P1477 is present; check for related codes
Inspect the passenger side fan for physical damage, binding, or debris
Test the fan motor by applying direct battery power and ground; if it doesn't run, replace motor
Check the fan fuse and relay; replace if blown or faulty
Inspect wiring and connectors for damage, corrosion, or loose connections; repair as needed
If all else passes, test the PCM output signal to the fan; if missing, suspect PCM failure
1. Frequently Asked Questions
Is it safe to drive?▼
No, it is not safe to drive with this code. The passenger side cooling fan is critical for engine and A/C cooling. Driving could lead to engine overheating, A/C failure, and potential engine damage. Have the vehicle repaired immediately.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on the root cause. A fan motor replacement averages $200-$400, while a relay or fuse is under $50. PCM replacement is rare and can exceed $800.