What is SPN 5357 FMI 31
- SPN 5357: Refers to a fault related to the diesel exhaust fluid (DEF) dosing system, indicating a problem with the DEF injector.
- FMI 31: Indicates a problem with the sensor or actuator within the DEF dosing system, often due to a fault in the system's performance or failure to inject the correct amount of DEF.
Together, SPN 5357 FMI 31 indicates that the DEF dosing system is not functioning as expected, which could lead to increased emissions or engine performance issues.
Why It Happened
This fault is typically caused by:
- A malfunctioning DEF injector.
- Blocked or clogged DEF lines or nozzles.
- Wiring issues or faulty sensors within the DEF system.
- Incorrect DEF fluid quality or contamination in the system.
- A failure in the ECM processing the DEF dosing data.
How to Resolve It
To resolve SPN 5357 FMI 31:
- Inspect the DEF injector and replace if it is malfunctioning.
- Check for blockages in the DEF lines or nozzles.
- Inspect wiring and connections in the DEF dosing system for damage.
- Test the DEF system components and ECM for proper functioning.
- After repairs, clear the fault code and restart the engine.
How to Avoid Before It Happens
To prevent SPN 5357 FMI 31:
- Regularly check and clean the DEF dosing system and injectors.
- Ensure DEF fluid is of the correct quality and free from contaminants.
- Use Clue to monitor DEF system data and get early alerts on any issues.
