Detailed guide for SPN 3364 FMI 4
Back to top ↑The DEF quality sensor tells the system if the fluid meets quality specs. A low voltage reading usually points to wiring/ground problems, not the sensor itself, so check harness first.
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Share ↓SPN 3364 FMI 4Severity: Warning
SPN 3364 FMI 4: DEF quality sensor voltage below normal – incorrect DEF quality readings
Quick Answer
DEF quality sensor voltage below normal – incorrect DEF quality readings
Code
SPN 3364 FMI 4
Severity
Warning
Applies to
Check OEM application
Can I drive?
Driving suitability is not established by this code alone.
Common Symptoms
- DEF quality alert
- Unexpected derate chances
- Often triggers after DEF fill
Likely Causes
- Low sensor voltage
- Bad sensor ground
- Connector contamination
Common Fixes
- Check wiring and ground
- Replace DEF quality sensor
- Verify DEF quality after fixing
Full technical sections↓
What does SPN 3364 FMI 4 mean?
Back to top ↑DEF quality sensor voltage below normal – incorrect DEF quality readings
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