12. Electrical System
186
12.7 Warning Devices
12.7.1 Oil pressure alarm
If the engine oil pressure is below 0.01-0.03MPa (0.1-
0.3kgf/cm
2
, 1.42-4.26 lb/in.
2
), with the main switch in
the ON position, the contacts of the oil pressure are
closed by a spring and the lamp is illuminated through
the lamp
oil pressure switch
ground circuit
system. If the oil pressure is normal, the switch contacts
are opened by the lubricating oil pressure and the lamp
remains off.
Inspection
Problem
Inspection Item
Inspection method
Corrective action
Lamp not
illuminated when
main switch set
to ON
1. Oil pressure lamp
blown out
(1) Visual inspection
(2) Lamp not illuminated even
when main switch set to ON
position and terminals of oil
pressure switch grounded
Replace the circuit of
panel
2. Operation of oil
pressure switch
Lamp illuminated when checked as
described in (2) above
Replace oil pressure
switch
Lamp not
extinguished
while engine
running
1. Oil level low
Stop engine and check oil level with
dipstick
Add oil
2. Oil pressure low
Measure oil pressure
Repair bearing wear
and adjust regulator
valve
3. Oil pressure
faulty
Switch faulty if abnormal at (1) and
(2) above
Replace oil pressure
switch
4. Wiring between
lamp and oil
pressure switch
faulty
Cut the wiring between the lamp
and switch and wire with separate
wire
Repair wiring harness
Cylinder block
OPTIONAL
Oil pressure
sender
Damper
Oil pressure switch
Fuse
Oil pressure
(Oil pressure alarm circuit)
Battery
Main switch
Alarm buzzer
Pilot lamp
Oil pressure switch
(Oil pressure switch)
Spring
Oil pressure
Contacts