
RENR9348-01 97
Troubleshooting Section
E. Check the allen head screw on each ECM
connector for t
he proper torque. Refer to the
diagnostic functional test Troubleshooting,
“Electrical Connectors - Inspect” for the correct
torque values
.
F. Check the harness and the wiring for abrasion
and for pinch
points from the air shutoff solenoid
to the ECM .
Expected Res
ult:
All connectors, pins, and sockets are completely
coupled and/
or inserted, and the harness and wiring
are free of corrosion, of abrasion and of pinch points.
Results:
•
OK – The connectors and wiring appear to be OK.
Proceed to Te
st Step 2.
•
Not OK – The connectors and/or wiring are not
OK.
Repair: Repair the wiring and/or the connectors.
Replace par
ts, if necessary. Ensure that all of the
seals are properly in place and ensure that the
connectors are completely coupled. Verify that the
problem is r
esolved.
STOP.
Test Step 2. Test the Operation of the
Control Solenoid for the Air Shutoff Relay
A. Turn the ba
ttery disconnect switch to the ON
position.
B. Test the ai
r shutoff system with the emergency
stop switch:
a. Place the e
mergencystopswitchintheSTOP
position.
b. Check the
position of the air shutoff valves.
Activation of the emergency stop will
activate the air shutoff system and the valve
mechanis
ms will close.
Check that the solenoids have de-energized
after th
e valves are closed. During an
emergency stop, the air shutoff timer will
activate the solenoids for 2.5 seconds.
c. Turn the battery disconnect switch to the OFF
position.
Reset the valve mechanisms to the open
position.
Place the emergency stop switch in the RUN
position.
C. Test the air shutoff system with the “Overspeed
Verify” featur
einCatET:
a. Connect Cat ET to the service tool connector.
b. Turn the battery disconnect switch to the ON
position.
c. Start the engine and allow the engine to run
at low idle.
d. Use Cat ET to activate the “Overspeed Verify”
feature. Wait at least 30 seconds for activation
of the featur
e.
e. Increase engine speed to the rated speed of
the engine.
f. Check the position of the air shutoff valves. An
engine overs
peed will activate the air shutoff
system and the valve mechanisms will close at
75 percent of the rated engine speed.
g. Turn the battery disconnect switch to the OFF
position.
Reset the valve mechanisms to the open
position.
Expected Result:
The valve me
chanisms operate correctly at this time.
Results:
•
OK – The valve mechanisms are operating
correctly.
Repair: The air shutoff system appears to be
operating correctly. The original problem seems to
be resolve
d. There may be an intermittent problem
in the harness or in a connector. If an intermittent
problem is suspected, refer to the diagnostic
functiona
l test Troubleshooting, “Electrical
Connectors - Inspect” for information that is related
to troubleshooting intermittent problems.
STOP.
•
Not OK - Eme
rgency Stop Switch – The valve
mechanisms do not close when the emergency
stop switch is activated. There is a problem with the
circuit f
or the emergency stop switch. There may
be a problem with the air shutoff timer. Proceed
to Test Step 3.
•
Not OK - Overspeed Verify – The valve
mechanisms do not close when the overspeed
verify f
eature is activated. There is a problem in
the harness from the ECM to the air shutoff relay.
There may be a problem with the circuit from the
relay to
the air shutoff solenoids. Proceed to Test
Step 6.