2009 Yamaha F40 Outboard Service Manual, Page 134Get this manual
Electrical system
Speed sensor output voltage (reference data): Blue (L)Black (B) 2.5 at 392.0 kPa (3.92 kgfcm2, 56.8 psi) 4.5 at 784.0 kPa (7.84 kgfcm2, 113.7 psi) 5Turn the engine start switch to "OFF," and then disconnect the test harness and the pressure pump a6Disconnect the engine ECM coupler b
PTT electrical system
Checking the PTT relay
1Measure the input voltage between the PTT relay terminal and the terminal bPTT relay input voltage: Terminal aTerminal 12.0 (battery voltage)
7Check the wiring harness for continuity3 1