Home / Generac / RPM Sensor Loss
Nexus
RPM Sensor Loss
RPM sensor loss
Engine · Alarm
The Nexus manual's RPM sensor failure alarm: if the controller does not see a valid RPM signal within three seconds of cranking, it shuts down and latches RPM Sensor Loss. If the signal disappears for one full second while running, it shuts down, waits 15 seconds, and re-cranks. If the signal is lost again, it latches out. The manual says a common cause is that the engine is not cranking at all.
Seen on: Air-cooled generators with the Nexus controller covered by the Nexus diagnostic manual.
Likely causes
- No crank, from the crank circuit or the starter, so there is no RPM to sense.
- RPM signal lost while running, followed by one re-crank attempt.
Checks an owner can do
- Check that the battery cables are tight and the battery is charged.
- Do not keep commanding a start after it latches.
When to call a pro
Starter and crank-circuit tests are in the service manual.
Source
Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.
What fixed mine
No approved reports for this code yet. Send one. It stays in the review queue until it is approved.
Related Generac codes
https://generatorcodes.com/brand/generac/nexus-rpm-sensor-loss