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SPN 164 FMI 1 — Injection control pressure low (HEUI — older engines)
SeriousEnginePower derate likely — plan to stop soon
Applies to: Navistar · HEUI systems only
Injection control pressure low (HEUI — older engines).
Don't risk it — get a diesel tech on the truck.
Your SPN/FMI rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- IPR valve
- High-pressure oil pump
- Injector oil rail leaks
First moves (roadside)
- Test HP oil system per MaxxForce procedure
FAQ
What does SPN 164 FMI 1 mean?
Injection control pressure low (HEUI — older engines).
How serious is SPN 164 FMI 1?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of SPN 164 FMI 1?
The most common cause is: IPR valve. Other possibilities include High-pressure oil pump; Injector oil rail leaks.
Can I keep driving with SPN 164 FMI 1?
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.