
RENR5622 79
Troubleshooting Section
Test Step 2. Inspect Electrical Connector s
and Wiring
A. Remove electrical power from the engine ECM.
B. Thoroughly in
spect the J1/P1 and J2/P2 ECM
connectors. Inspect the connector for the coolant
flow switch. Refer to Troubleshooting, “Inspecting
Electrical C
onnectors” for details.
C. Perform a 45 N (10 lb) pull test on each of the
wires in the E
CM connector and the sensor
connectors that are associated with the active
diagnostic code.
D. Check the ECM connectors (allen head screw)
for the proper torque. Refer to Troubleshooting,
“Inspecting
Electrical Connectors” for details.
E. Check the harness and wiring for abrasions and
for pinch po
ints from the sensors back to the ECM.
Expected Result:
All connectors, pins, and sockets are completely
inserted and coupled. The harness and wiring are
free of corr
osion, of abrasion, and of pinch points.
All connections and grounds are tight and free of
corrosion.
Results:
•
OK – The har
ness and wiring are OK. Proceed
to Test Step 3.
•
Not OK – The
re is a problem in the connectors
and/or wiring.
Repair: Re
pair the connectors or wiring and/or
replace the connectors or wiring. Ensure that all of
the seals are properly in place and ensure that the
connecto
rs are completely coupled.
Verify that the repair eliminates the problem.
STOP.
Test Step
3. Check the Status of the
Coolant F
low o n Caterpillar Electronic
Technic
ian (ET)
A. Restore electrical power to the engine ECM.
B. Connect Cat ET to the service tool connector.
C. Observe
the reading for coolant flow on Cat ET.
D. Turn the keyswitch to the START po sition. Start
the engi
ne.
E. Observe the reading for coolant flow on Cat ET.
F. Turn the keyswitch to the OFF position.
Expected Result:
Cat ET indicates “NO FLOW” while the engine is not
running. Cat ET indicates “FLOW” while the engine
is running.
Results:
•
OK – Cat ET indicates “NO FLOW” while the
engine is not running. Cat ET indicates “FLOW”
while the engi
ne is running. The coolant switch is
OK.
Repair: If th
e problem is intermittent, perform
the diagnostic functional test Troubleshooting,
“Inspecting Electrical Connectors”.
STOP.
•
Not OK – Cat ET
does not indicate “NO FLOW”
while the engine is not running. Cat ET does not
indicate “FLOW” while the engine is running. Cat
ET does not i
ndicate the correct status of the
coolant flow switch. Proceed to Test Step 4.
Test Step 4.
Create a Short Circuit at the
Connector o
f the Coolant Flow Switch
A. Disconnect the connector for the coolant flow
switch.
B. Use a suitable piece of wire to short terminal 1
(coolant f
low switch) to terminal 2 (engine ground).
C. Turn the keyswitch to the ON position.
D. Observe the status of “Engine Coolant Flow” on
Cat ET.
E. Turn the keyswitch to the OFF position.
Expected R
esult:
The status indicates “Flow” with the jumper wire in
place.
Results:
•
OK – The ECM and the wiring are operating
correctly. Proceed to Test Step 5.
•
Not OK – The status indicates “NO FLOW”.
ProceedtoTestStep6.