DEF Dosing Valve Circuit Open (J1939)
The VOLVO-MACK-SPN3361-FMI5 (Volvo/Mack D/MP Series) diesel fault code means: DEF Dosing Valve Circuit Open (J1939). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $400-$2,500
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Common Symptoms
- Check Engine Light illuminated
- Possible engine derate
- Warning message on driver display
- System-specific warning lamp (DPF/DEF/coolant/etc.)
Probable Causes (Ranked by Likelihood)
- DEF doser open-circuit or harness damage Very Likely
- DEF doser solenoid failed internally Likely
- Connector corrosion at doser Possible
- ACM output driver fault Less Likely
Step-by-Step Diagnostic Procedure
Connect Volvo PTT or Mack Guided Diagnostics and verify DEF doser open-circuit fault.
Measure doser solenoid resistance (spec per service manual).
Inspect connector and pin integrity at the doser.
If solenoid and wiring test good, suspect ACM driver; further testing required.
Run DEF dosing test after repair.
Frequently Asked Questions
What does Volvo/Mack code SPN3361-FMI5 mean?
Volvo/Mack code SPN3361-FMI5 (DEF Dosing Valve Circuit Open (J1939)) is a serious-severity diagnostic trouble code set on D11/MP7, D13/MP8, and D16/MP10 diesel engines in Volvo VNL/VNR and Mack Anthem/Pinnacle/Granite/Titan trucks. It indicates a fault in the DEF doser system and should be read with Volvo Premium Tech Tool (PTT) or Mack Guided Diagnostics.
Can I drive a Volvo or Mack truck with code SPN3361-FMI5?
Short distances may be acceptable to reach a repair facility, but the fault will escalate to derate (typically 55 mph then 5 mph on aftertreatment faults). Do not defer diagnosis beyond a shift.
How much does it cost to fix Volvo/Mack code SPN3361-FMI5?
Typical repair falls in the range $400-$2,500. Sensor/wiring repairs are at the low end; EGR cooler, NOx sensor set, DEF pump, injector, or head work runs at the high end. Volvo PTT or Mack Guided Diagnostics is normally required for calibration and parameter programming.
Sources
This page is built from documented references. Verify against your own service info before repair work.