Active Regen Inhibited
The DD-3713-31 (Detroit Diesel DD Series) diesel fault code means: Active Regen Inhibited. This is a moderate severity code.
This is a standard J1939 fault, not a proprietary code. DD-3713-31 is how this equipment displays SPN 3713 with FMI 31 (condition exists) under the SAE J1939 standard used across heavy equipment. The same SPN can appear on any J1939-compliant machine regardless of brand — so cross-referencing it against your engine maker's documentation is valid even when the equipment brand differs.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $500-$2,200
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What Are the Symptoms of DD-3713-31?
- Check Engine Light / Amber Warning Lamp illuminated
- DPF regen inhibited or failing
- DPF fill increasing
What Causes DD-3713-31? (Most Likely First)
- Upstream fault blocking regen Very Likely
- Low coolant temp preventing regen authorization Likely
- Operator inhibit switch stuck Possible
Can I Still Drive with DD-3713-31?
Yes, but fix soon. DD-3713-31 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring it.
Frequently Asked Questions
What is Detroit Diesel fault code DD-3713-31?
Detroit Diesel fault DD-3713-31 (SPN 3713 FMI 31) indicates: Active Regen Inhibited. It is a moderate-severity fault and is commonly seen on DD13/DD15/DD16 engines in Freightliner and Western Star chassis.
Can I drive my Freightliner or Western Star with fault DD-3713-31?
It depends on severity. Critical and serious faults trigger derate or engine shutdown — do not continue driving. Moderate faults usually allow continued operation short-term but schedule repair to prevent cascading aftertreatment damage.
How much does it cost to fix Detroit Diesel fault DD-3713-31?
Estimated repair cost is $500-$2,200. Sensor/harness fixes fall at the low end; turbo actuator, injector, aftertreatment component, or head gasket repairs fall at the high end. Detroit DDDL software and sometimes factory parameter reset are required for proper reset.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose DD-3713-31?
Read all active faults first — regen inhibit is a symptom.
Confirm coolant temp is reaching operating range.
Verify PTO/inhibit switch is not active.
Initiate parked regen via DDDL once upstream faults are cleared.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- Perkins 404F-22 Engine Fault Codes table, printed in the Genie S-80/S-85/S-80X Service Manual, Part No. 1259369GT, February 2017printed page 170: SPN 3713 FMI 31, "DPF Active Regeneration Inhibited Due to System Timeout". The table is that engine maker's; it establishes what the J1939 SPN-FMI pair means, not that a Detroit Diesel display shows it.
Which Vehicles Commonly Get DD-3713-31?
- Freightliner Cascadia with DD15
- Freightliner Cascadia with DD13
- Freightliner Cascadia with DD16
- Western Star 4700 with DD13/DD15
- Western Star 4900 with DD15/DD16
- Western Star 5700 XE with DD15
- Freightliner M2 106 with DD13
- Freightliner M2 112 with DD13
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