SPN 190 FMI 1
Volvo Penta
Engine Speed Sensor Circuit Fault
Engine speed signal lost; ECU logs no RPM; engine may crank but not start or may shut down.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Failed flywheel speed sensor, Damaged sensor wiring harness, Excessive sensor gap to tone wheel, Contamination on tone wheel teeth
How to Fix / Troubleshooting
Safety: Disable auto-start and ensure the engine cannot crank while working near the flywheel housing.
- Locate speed sensor: Typically mounted on the flywheel housing or crankshaft pulley area.
- Inspect and clean: Remove the sensor and inspect the tip for metal filings or damage. Clean with a lint-free cloth. Check the tone wheel for broken or missing teeth.
- Check air gap: Reinstall the sensor and set the air gap according to Volvo Penta specifications (often using a feeler gauge). Too large a gap can cause signal loss.
- Test wiring: Verify continuity from the sensor connector to the ECU. Repair any damaged wires and secure the harness away from hot or moving parts.
- Replace sensor if needed: If wiring is good and the fault persists, install a new Volvo Penta speed sensor.
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Repair Difficulty
Medium
3/5
Required Part
Flywheel Speed Sensor
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