Cummins ISB 6.7 SPN 3055 FMI 14 — DPF Condition (Parked Regeneration Required)

Code Details

Plain-English Meaning

The Cummins ISB 6.7 DPF regenerates automatically during normal highway driving when exhaust temperatures are high enough to passively oxidize accumulated soot. When driving conditions do not produce adequate exhaust temperatures for passive regen, the ECM commands an active regen by instructing the 6th injector to spray fuel into the exhaust to raise DPF temperatures. When neither passive nor active driving regen can keep pace with soot accumulation — typically because the application involves frequent stops, low-speed operation, or short trips — the soot load eventually reaches the level where a parked regen is needed. A parked regen runs the ISB 6.7 at elevated idle in a stationary vehicle, using the 6th injector to maintain high DPF temperatures for an extended cycle to burn off the accumulated soot. SPN 3055 FMI 14 is the ECM notification that this parked regen is now required to restore normal DPF operation.

SPN 3055 is Aftertreatment 1 Diesel Particulate Filter Condition; FMI 14 is a condition-exists flag indicating soot load has reached the parked regen request threshold. On the Cummins ISB 6.7 (CM2350 B101), the ECM tracks DPF soot load through exhaust pressure differential measurement across the filter. When the calculated soot load percentage reaches the parked regen threshold, SPN 3055 FMI 14 is set and the driver is notified to initiate a parked regen. Cummins INSITE displays the current soot load percentage, regen history, and regen inhibit status. INSITE can also initiate a service-level parked regen remotely to monitor the cycle progress in real time. The soot load reading before and after the parked regen confirms whether the cycle completed successfully.

Common Symptoms

• DPF regeneration required lamp and/or message on the instrument cluster or driver display
• Possible engine derate if the parked regen request has been delayed
• Reduced performance during stop-and-go driving or under load at lower speeds
• Engine idling at an elevated speed with the parking brake engaged (during an in-progress parked regen)

Possible Causes

Possible causes may include the items below. The list is not a parts diagnosis.

• High-idle or low-speed duty cycle preventing driving regen exhaust temperatures from being reached
• Repeated driver interruptions of driving regen cycles during highway operation
• Short-trip operation where coolant temperature and exhaust temperature do not reach regen-capable levels
• DPF differential pressure sensor fault causing incorrect soot load calculation
• 6th injector fault preventing active driving regens from completing effectively

First Checks

• Initiate a parked regen following the instrument cluster prompts with the vehicle stationary in a safe outdoor location with the parking brake set
• Connect Cummins INSITE to monitor DPF soot load before the regen and confirm the reading drops during and after the cycle
• If the parked regen does not complete, check INSITE for any active inhibit conditions — low fuel level, coolant temperature out of range, or a 6th injector fault — that may be preventing the regen cycle from running
• Review the regen history in INSITE to determine how many driving regens were attempted and how many completed before the parked regen was required
• After a successful parked regen, discuss duty cycle with the operator to identify whether operational changes can reduce the frequency of parked regen events

Can I Keep Driving?

The truck is driveable when this fault first sets but may have a speed or power limitation. Complete the parked regen promptly to prevent further soot accumulation and escalation to a more severe derate.

Related Lookup Pages

• FMI 14 explanation
• Cummins manufacturer hub
• Aftertreatment fault codes
• Search this code