Code Details
| Display code | SPN 3055 FMI 14 |
|---|---|
| SPN | 3055 |
| FMI | 14 |
| OEM code | None listed |
| Manufacturer | Mack |
| System | Aftertreatment �?DPF |
| Component | DPF / regeneration system / aftertreatment control |
| Source address | Unknown or not applicable |
| Severity | medium |
| Review status | source backed |
| Source confidence | medium |
| Last reviewed | 2026-06-12 |
Plain-English Meaning
The Mack MP8 shares the same basic DPF regen architecture as the Volvo D13 �?both use exhaust pressure differential to calculate soot load and both use an active regen system with a dosing injector. SPN 3055 FMI 14 appears when the soot load is too high for driving regen to manage. On Mack Anthem, Pinnacle, and Granite vocational trucks, short-haul routes or stop-and-go urban delivery work significantly increases the frequency of parked regen requests due to lower average exhaust temperatures. On Mack Anthem, Pinnacle, and Granite trucks with the MP8, the DPF regen inhibit reason is available in VCADS Pro (PTT). On Mack vocational trucks with PTOs engaged for pumping or lifting operations, the PTO active state inhibits regen to prevent aftertreatment temperature events near flammable materials or personnel. If SPN 3055 FMI 14 is occurring only during PTO operation, this is expected system behavior and not a fault requiring repair. The DPF soot load should be evaluated when PTO work is complete to determine if a parked regen is needed.
SPN 3055 FMI 14 is DPF Condition �?parked regen required. On Mack MP8 with EMS3, VCADS Pro (or PTT �?Premium Tech Tool) provides DPF soot load, regen history, and the ability to force a parked regen for service use. The soot load threshold for a parked regen request is calibration-specific and can be viewed in VCADS Pro.
Common Symptoms
- DPF regen required warning on the Mack instrument panel
- Potential engine power or speed limitation if deferred
- Often associated with urban delivery, vocational, or short-haul operation
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Short-haul or urban driving preventing adequate exhaust temperature for driving regen
- Repeated driver inhibition of regen requests in vocational settings
- Multiple short trips that never allow full regen completion
- DPF pressure differential sensor fault generating incorrect soot load reading
First Checks
- Perform a parked regen per the Mack driver display procedure in a safe, open area
- Connect VCADS Pro to confirm DPF soot load before and after the regen
- Review regen history and inhibition events to understand the operating pattern
- For vocational trucks with frequent parked regen requests, evaluate if route modification or driver training can reduce regen frequency
- Identify the specific regen inhibit reason in VCADS Pro — confirm whether PTO or speed inhibit is the cause
- After PTO operations, connect VCADS Pro and check DPF soot load to determine if a parked regen is needed
Can I Keep Driving?
Driveable but with escalating derate if regen is not completed. Address as soon as operationally safe.
Related Codes
Related Lookup Pages
Sources
- Mack Trucks Service Support Public Resources Mack Trucks Inc. · oem · accessed 2026-06-11 · confidence medium
Source: Mack Trucks Inc., Mack Trucks Service Support Public Resources. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - Volvo Trucks / Mack Trucks Technical Support Volvo Trucks North America / Mack Trucks Inc. · oem · accessed 2026-06-10 · confidence medium
Source: Volvo Trucks North America / Mack Trucks Inc., Volvo Trucks / Mack Trucks Technical Support. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - SAE J1939 Standards Collection SAE International · official · accessed 2026-05-05 · confidence medium
Source: SAE International, SAE J1939 Standards Collection. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
Why do Mack Granite vocational trucks require parked regens more often than Mack Anthem highway trucks?
Vocational trucks like the Mack Granite typically operate at lower average vehicle speeds with frequent stops, idling, and low-load cycles. These conditions produce lower exhaust temperatures that do not support passive or mild active DPF regen during driving. Highway trucks achieve sustained high exhaust temperatures that allow driving regens to keep the DPF clean without parked regen interventions.
Can the Mack MP8 DPF regen be turned off to avoid interrupting vocational operations?
Inhibiting DPF regen is possible in some configurations for specific vocational situations (fueling areas, enclosed buildings), but the inhibition must be temporary. Permanently disabling DPF regen causes soot accumulation that will escalate to a severe derate and eventual engine protection shutdown. Mack provides regen inhibit strategies in some calibrations for vocational applications �?contact a Mack dealer for the appropriate inhibit procedure.
Is the Mack MP8 parked regen procedure the same as the Volvo D13?
The regen system architecture is shared between the Mack MP8 and Volvo D13, but the driver interface and prompts differ by brand. The Mack Anthem/Pinnacle/Granite display has Mack-specific messaging and procedures. The underlying VCADS Pro (PTT) service regen function is equivalent �?both platforms use the same software platform with a different brand interface.