Test 42 - Check Oil Pressure Switch And Wire 86; Test 43 - Check Start Stop Relay (Ssr) - Generac Power Systems GP Series Diagnostic And Repair Manual

Section 4 AC Diagnostic Tests
Test 42 – Check Oil Pressure Switch
and Wire 86
•
If the engine cranks and starts, then shuts down
almost immediately, the cause may be one or more
of the following:
• Low engine oil level
• Low oil pressure
•
A defective oil pressure switch
Figure 4-52. Low Oil Pressure Switch
Procedure
Check engine crankcase oil level. If necessary, add
1.
the recommended oil to the dipstick FULL mark.
NOTE: Do not overfill above the full mark.
Disconnect wire 86 and wire 0 from the oil pressure
2.
switch terminals.
Remove the switch and install an oil pressure
3.
gauge in its place.
Start the engine while observing the oil pressure
4.
reading on gauge. Normal oil pressure is
approximately 35-40 psi with engine running.
a. If normal oil pressure is indicated, go to step
11 of this test.
b. If oil pressure is below about 10 psi, shut
engine down immediately. A problem exists in
the engine lubrication system.
NOTE: The oil pressure switch is rated at 10 psi for v-
twin engines.
NOTE: Refer to Service Manual, Generac P/N 0F6923
for engine service recommendations.
Remove the oil pressure gauge and install the oil
5.
pressure switch.
NOTE: Do not connect wire 86 or wire 0 to the switch
terminals.
Set DMM to measure resistance.
6.
Connect the meter test leads across the switch
7.
terminals.
a. With engine shut down, Continuity should be
measured.
58
Crank and start the engine.
8.
a. Infinity should be measured.
Connect one test lead to wire 0 (disconnected from
9.
LOP).
Connect the other test lead to a clean frame
10.
ground.
a. Continuity should be measured.
b. If continuity is not measured repair or replace
wire 0 between the LOP and the ground
terminal connection on the engine mount.
If the LOP switch tests good in steps 5-10 and oil
11.
pressure is good in steps 2-4, but the unit still shuts
down with a LOP fault, check wire 86 for a short to
ground.
Set DMM to measure resistance.
12.
Disconnect the J2 connector from the circuit board.
13.
Remove wire 86 from the LOP switch.
14.
Connect one test lead to wire 86.
15.
Connect the other test lead to a clean frame
16.
004663
ground.
a. Infinity should be measured.
b. If Continuity is measured, repair or replace
wire 86 between the LOP switch and the J2
connector.
Results
If switch tests good, refer to Flow Chart.
1.
Replace switch if it fails the test.
2.

Test 43 - Check Start Stop Relay (SSR)

Procedure
Set DMM to measure resistance.
1.
See Figure
2.
from the Start Stop Relay (SSR).
14
15
15
15
Figure 4-53. Testing Start Stop Relay (SSR)
Connect one meter test lead to the terminal that
3.
wire 15 was removed from.
Connect the other meter test lead to the terminal
4.
that wire 229 was removed from.
4-53. Disconnect wire 15 and wire 229
18
1 2 4
15B
5 6 8
9 10 12
0
13 14
SSR
229
Diagnostic Repair Manual
004630