Active Regen Inhibited
The DD-3713-31 (Detroit Diesel DD Series) diesel fault code means: Active Regen Inhibited. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $500-$2,200
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Common Symptoms
- Check Engine Light / Amber Warning Lamp illuminated
- DPF regen inhibited or failing
- DPF fill increasing
Probable Causes (Ranked by Likelihood)
- Upstream fault blocking regen Very Likely
- Low coolant temp preventing regen authorization Likely
- Operator inhibit switch stuck Possible
Step-by-Step Diagnostic Procedure
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.
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?
Typical 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.
Sources
This page is built from documented references. Verify against your own service info before repair work.