Fujitsu Mini Split Error Code 42: How to Fix It

Q: What causes Fujitsu error code 42?

Error code 42 is caused by a faulty outdoor heat exchanger middle temperature sensor. This can happen due to sensor failure, loose wire connections, corrosion, or physical damage to the sensor from weather or debris.

Q: Can I run my Fujitsu mini split with error code 42?

You should not continue running the unit with error code 42. The faulty temperature sensor can cause improper system operation, reduced efficiency, and potential damage to other components like the compressor.

Q: How much does it cost to fix Fujitsu error code 42?

If you replace the sensor yourself, the part typically costs $20-50. Professional repair usually ranges from $150-300 including labor, depending on accessibility and local rates. The sensor itself is inexpensive, but labor for diagnosis and replacement adds to the cost.

Q: How do I prevent Fujitsu error code 42 from happening again?

Regular maintenance helps prevent sensor failures. Keep the outdoor unit clean and free of debris, schedule annual professional maintenance, and protect the unit from extreme weather when possible. Ensure proper installation with adequate clearance around the outdoor unit.

Q: Is Fujitsu error code 42 covered under warranty?

Coverage depends on your unit's age and warranty terms. Most Fujitsu mini splits have a 5-year parts warranty that would cover sensor replacement. Check your warranty documentation or contact Fujitsu customer service with your model and serial number.

Abstract

Error code 42 on your Fujitsu mini split indicates a malfunction with the outdoor heat exchanger middle temperature sensor. This sensor monitors the temperature of the outdoor coil to ensure proper system operation, and when it fails, your unit may not heat or cool efficiently.