Home › Fault codes › SPN 1127 FMI 0
SPN 1127 FMI 0 — Turbo boost pressure high
SeriousEnginePower derate likely — plan to stop soon
Applies to: Navistar · Paccar · Volvo
Turbo boost pressure high.
Don't risk it — get a diesel tech on the truck.
Look up listed providers near you and give them this SPN/FMI when you call.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Overboost
- Stuck VGT
- Stuck VGT vanes
- VGT stuck
First moves (roadside)
- Compare live data
- Live data compare
- Actual vs commanded
FAQ
What does SPN 1127 FMI 0 mean?
Turbo boost pressure high.
How serious is SPN 1127 FMI 0?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of SPN 1127 FMI 0?
The most common cause is: Overboost. Other possibilities include Stuck VGT; Stuck VGT vanes; VGT stuck.
Can I keep driving with SPN 1127 FMI 0?
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
Find a mechanic or related guides
General diagnostic guidance for heavy-duty diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack). Not a substitute for a scan-tool diagnosis on your specific truck.