Detailed guide for SPN 3363 FMI 3
Back to top ↑SPN 3363 FMI 3 – DEF tank heater voltage high
Most often: wiring damage near the tank/frame rails.
✅ Fix
- Find the rub point, repair wiring, protect with loom and proper clips.
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Share ↓SPN 3363 FMI 3Severity: Warning
SPN 3363 FMI 3: DEF tank heater voltage high (short to power / wiring fault)
Quick Answer
DEF tank heater voltage high (short to power / wiring fault)
Code
SPN 3363 FMI 3
Severity
Warning
Applies to
Check OEM application
Can I drive?
Driving suitability is not established by this code alone.
Common Symptoms
- Intermittent DEF heater faults
- Electrical codes after heavy slush/salt exposure
- Heater may behave erratically
Likely Causes
- Short to power in harness
- Pinched wire / insulation damage
- Connector contamination causing bridging
Common Fixes
- Inspect harness for rub-through and pinched sections
- Clean and dry connectors, repair damaged pins
- Verify proper voltage at control side during commanded states
Full technical sections↓
What does SPN 3363 FMI 3 mean?
Back to top ↑DEF tank heater voltage high (short to power / wiring fault)
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