What is SPN 3359 FMI 18
- SPN 3359: Refers to a fault in the refrigerant pressure sensor of the air conditioning (A/C) system, indicating that the refrigerant pressure is higher than expected.
- FMI 18: Indicates that the sensor has provided an invalid signal or the data is out of range, meaning the ECM cannot interpret the sensor readings accurately.
When SPN 3359 FMI 18 appears, it means there is a refrigerant pressure issue, possibly caused by excessive pressure in the A/C system, which could lead to malfunctioning A/C performance or damage to the system.
Why It Happened
This fault is commonly caused by:
- A faulty refrigerant pressure sensor that is providing inaccurate data.
- Excessive refrigerant pressure due to an overcharged A/C system.
- Blockages or restrictions in the refrigerant lines, causing pressure buildup.
- A malfunctioning A/C compressor or other related components affecting the pressure.
- Wiring or connection issues between the sensor and ECM that affect signal transmission.
How to Resolve It
To resolve SPN 3359 FMI 18:
- Inspect the refrigerant pressure sensor for any damage, and replace it if necessary.
- Check the refrigerant levels to ensure the system is not overcharged. If overcharged, safely release excess refrigerant.
- Inspect the refrigerant lines and A/C components for blockages or malfunctions, such as a failing compressor.
- Verify the sensor's wiring and connections for damage or corrosion and repair as needed.
- After repairs, clear the fault code and restart the system to confirm the fix.
How to Avoid Before It Happens
To prevent SPN 3359 FMI 18:
- Regularly check and maintain the refrigerant pressure sensor and A/C system components.
- Ensure proper refrigerant charge according to manufacturer specifications.
- Monitor refrigerant pressure data with tools like Clue to receive real-time alerts on pressure issues.
- Optimize construction equipment management to prevent delays and avoid operational hiccups.
