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Detroit Diesel SPN 5246 FMI 0 indicates a malfunction within the aftertreatment system. This fault is commonly associated with SCR, DEF dosing, or sensor-related issues affecting emissions performance.
Symptoms
- Check engine light illuminated
- Aftertreatment warning message
- DEF system alerts
- Reduced engine power
- Possible derate condition
Cause
This code is typically triggered by DEF dosing problems, NOx sensor failure, wiring issues, clogged SCR catalyst, or contamination within the aftertreatment system.
Can You Keep Driving?
Limited operation may be possible, but prolonged driving without repair may result in progressive derate or speed limitation.
Recommended Action
Inspect DEF system components, verify sensor functionality, and perform diagnostic testing on the SCR and aftertreatment system to identify the root cause.
SPN 5246 FMI 0 indicates that the SCR aftertreatment system has detected a condition that may trigger engine inducement, such as power reduction or speed limitation.
This code is commonly caused by DEF system faults, failed sensors, SCR efficiency issues, or repeated unresolved emissions-related errors.
Driving may be possible initially, but continued operation without repair can result in progressive engine derate or speed restriction.
Yes. If the issue is not corrected, the engine control module may reduce vehicle speed to enforce emissions compliance.
The fault will clear only after diagnosing and repairing the underlying SCR or DEF system issue. Clearing the code without repair will not prevent derate.
Related codes
Need Immediate Help With This Fault Code?
If your engine is derating, losing power, or unable to complete regeneration, don’t risk further damage or costly downtime.
Use 4RoadService to locate mobile truck repair, dealer diagnostics, or emergency roadside assistance near your location.
Important Notice
The information provided above is for general informational purposes only and should not replace official OEM service procedures. Always consult the manufacturer’s service manual or a qualified diesel technician before performing repairs. Operating a vehicle with active fault codes may result in further damage.