Yamaha F75F - Page 104

Engine control unit and component
5-20
Checking the ISC valve
1. Check:
• ISC valve operatio
n (using the YDIS “Sta-
tionary test”)
No operating sound 
Check the ISC
valve resistance.
2. Check:
• ISC valve
operation (using the YDIS “Ac-
tive test”)
No change in engine speed  Check the
ISC valve
resistance.
a. Start the engine, and then check that
the engine
speed increases using the
YDIS “Active test”.
b. Stop the engine.
3. Measure:
• ISC valve
resistance
Out of specification  Replace.
a. Disconnect the ISC valve coupler “a”.
b. Measure the resistance between the
ISC valve terminals.
c. Connect the ISC valve coupler.
Checking the oil pressure switch
1. Measure:
• Oil pressure switch input voltage
Out of specification  Check the
wire har-
ness for continuity.
a. Disconnect the oil pressure switch
lead “a”.
b. Turn the engine start switch to ON,
and then
measure the oil pressure
switch input voltage.
c. Turn the engine start switch to OFF.
d. Connect the oil pressure lead. See
“Wire harness” (7-19).
2. Check:
• Oil pressure switch continuity
Out of specification  Replace.
a. Remove the oil pressure switch “1”.
b. Connect the special service tool “2” to
the oil pressure switch “1”.
Resistance
27.0–33.0 
a
Oil pressure switch input voltage
12 V
Pink/White (P/W)–Ground
a
P/W