2009 Yamaha F40 Outboard Service Manual, Page 112Get this manual
Electrical system Wiring harness continuity: PinkWhite (PW)Terminal 28 10Connect the engine ECM coupler b11Install the oil pressure switch and the oil pressure switch lead aSee "Installing the oil pressure switch" (7-49)
6Apply positive pressure to the oil pressure switch slowly, and then check that continuity changes to no continuity in the range of the working pressureReplace the oil pressure switch if the continuity does not change to no continuity in the working pressure range
Checking the alert buzzer
1Remove the alert buzzer2Connect the battery leads to the alert buzzer connectors, and then check that the alert buzzer comes onReplace the alert buzzer if it does not come on