SPN 190 FMI 2 — Engine speed sensor — erratic
What it means: Engine speed sensor — erratic.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Check sensor air gap
Don't risk it — look up listed providers near you and give them this SPN/FMI when you call.
Listed providers nearest Sparks, NV
Closest first. Tell them SPN 190 FMI 2 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Sparks, NV · (775) 355-6884
- 0.0 mi away — based in Sparks, NV · (775) 356-7200
- 0.0 mi away — based in Sparks, NV · (775) 359-0550
Applies to: Detroit · Navistar · Paccar · Volvo
What SPN 190 FMI 2 means
Engine speed sensor — erratic.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Crank sensor failing
- Tone wheel damage
- Air gap
- Harness issue
- Crank sensor
- Tone wheel
First moves (roadside)
- Check sensor air gap
- Inspect tone wheel
- Resistance check
- Inspect sensor
- Air gap inspection
- Resistance
- Sensor air gap and resistance
FAQ
Engine speed sensor — erratic.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Crank sensor failing. Other possibilities include Tone wheel damage; Air gap; Harness issue; Crank sensor; Tone wheel.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside SPN 190 FMI 2, or share the same subsystem.
- Engine speed signal abnormal update rate (SPN 190 FMI 9)
- Engine overspeed (SPN 190 FMI 16)
- Engine Protection — Power Derate Active (SPN 1569 FMI 31)
- Intake Manifold (Charge Air) Temp — High (SPN 105 FMI 0)
- Turbo Boost Pressure — High / Overboost (SPN 1127 FMI 16)
- Boost pressure high (SPN 102 FMI 0)
- Boost sensor — voltage low (SPN 102 FMI 4)
- Intake manifold temp — voltage high (SPN 105 FMI 3)
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.