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Nexus
Low Oil Pressure
Low oil pressure
Engine · Alarm
Nexus low oil pressure is a named shutdown. An oil-pressure switch on the oil-filter adapter has normally closed contacts held open by oil pressure. The manual says the contacts close if pressure drops below approximately 5 psi, which grounds wire 86. The controller then opens its run relay, closes the fuel shutoff solenoid, and drops ignition.
Seen on: Air-cooled generators with the Nexus controller covered by the Nexus diagnostic manual.
Likely causes
- Oil level low enough that pressure falls below about 5 psi.
- A switch that closes even though pressure is actually up.
- A real oil-pressure failure.
Checks an owner can do
- Engine off and cool: check the dipstick and correct the level only as the owner manual describes.
- Look for an obvious leak at the filter. Do not tighten a hot filter by guessing.
When to call a pro
If the level is right and the shutdown returns, pressure and the wire 86 switch circuit have to be tested. Do not bypass the switch.
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
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Related Generac codes
https://generatorcodes.com/brand/generac/nexus-low-oil-pressure