Active Regen Inhibited
What does DD-3713-31 mean?
The DD-3713-31 (Detroit Diesel DD Series) diesel fault code means: Active Regen Inhibited. This is a moderate severity code.
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.