Fault Shutdown Switches - Kohler 8.5RES Service Manual

5.9.2

Fault Shutdown Switches

Check the low oil pressure and high engine temperature
shutdown switches on the engine by performing the
following tests. If the sensor does not function as
described, replace it.
WARNING
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
are in place.
Servicing the generator set when it is operating. Exposed
moving parts can cause severe injury or death. Keep
hands, feet, hair, clothing, and test leads away from the belts
and pulleys when the generator set is running. Replace
guards, screens, and covers before operating the generator
set.
Short circuits. Hazardous voltage/current can cause
severe injury or death. Short circuits can cause bodily injury
and/or equipment damage.
connections with tools or jewelry while making adjustments or
repairs. Remove all jewelry before servicing the equipment.
Temperature Sensor (CTS)
The coolant temperature sensor (CTS) is used to
monitor engine temperature for the high engine
temperature fault shutdown (HE). See Section 1.8,
Service Views, for the coolant temperature sensor
location. Set the generator set master switch to the OFF
position and allow the generator set to cool. Disconnect
the CTS and use an ohmmeter to measure the
resistance across the sensor. The sensor resistance
varies with temperature and should be within the values
shown in Figure 5-17. If the resistance is very low
(indicated a short circuit) or very high (indicating an
open circuit) replace the CTS.
Note: The HET switch is located in the engine oil pan.
Drain the engine oil before removing the switch.
Temperature, _C (_F)
30 (86)
100 (212)
Figure 5-17 Coolant Temperature Sensor Resistance
Readings
TP-6196 5/04
Moving rotor.
Do not contact electrical
Resistance, Ohms
2100--2500
180--200
Low Oil Pressure (LOP) Switch
The low oil pressure (LOP) switch is located under the
engine air cleaner. See Figure 5-18.
Remove the LOP switch and install an oil pressure
gauge to verify that the engine oil pressure is within the
range specified in Section 1, Specifications, before
testing or replacing the LOP switch. To test the LOP
switch, reinstall the switch and start the generator set. If
the unit shuts down, disconnect lead 13 from the LOP
switch and reset the controller. Restart the generator
set and verify that it does not shut down. A successful
restart indicates a bad LOP switch. Replace the switch.
1
1. Oil pressure switch
Figure 5-18 Oil Pressure Switch Location (under the
air cleaner)
Section 5 Component Testing and Adjustment
tp6196
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