Troubleshooting

(Table 86, contd)
Troubleshooting Test Steps
Values Results
4. Check the Power Supply to the Suspect Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the battery supply wire from the suspect switch.
C. Turn the keyswitch to the ON position.
D. Check the voltage between the battery supply wire to the sus-
pect switch and a suitable ground.
10 V to 14 V Result: The measured voltage is within the ex-
pected range.
Proceed to Test Step 6.
Result: The measured voltage is not within the
expected range.
Proceed to Test Step 5.
5. Check the Wiring Between the Suspect switch and the
ECM Main Power Relay
A. Turn the keyswitch to the OFF position.
B. Disconnect the battery supply wire from the suspect switch.
C. Disconnect the ECM main relay.
D. Use a multimeter to measure the resistance between the dis-
connected wire and terminal 87 on the harness connector for the
ECM main relay.
Less than 5 Ohms Result: The measured resistance is greater than
5 Ohms.
The fault is in the wiring between the suspect
switch and the ECM main relay
Repair: Check all wiring between the suspect
switch and the ECM main relay. Refer to the Elec-
trical Schematic for the application.
Replace the faulty wiring.
Use the electronic service tool to clear all logged
diagnostic codes and verify that the repair elimi-
nates the fault.
Result: The measured resistance is less than 5
Ohms.
Repair: Refer to Troubleshooting, “Relay - Test
(ECM Main Relay)” in order to test the circuit for
the ECM main relay.
6. Create at Short Circuit at the Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the suspect switch.
C. Fabricate a jumper wire and install the jumper wire between
the two terminals for the switch.
D. Turn the keyswitch to the ON position.
E. Monitor the status screen on the electronic service tool while
the jumper wire is being disconnected and reconnected.
Switch status Result: When the jumper wire is connected, the
status of the suspect PTO switch is “CLOSED” .
When the jumper wire is disconnected, the status
of the suspect PTO switch is “OPEN” .
Repair: Replace the switch.
Use the electronic service tool in order to clear all
logged diagnostic codes and then verify that the
repair has eliminated the problem.
Result: When the jumper wire is disconnected,
the status of the suspect PTO switch is
“CLOSED” .
Reconnect the switch and proceed to Test Step
7.
Result: When the jumper wire is connected, the
status of the suspect PTO switch is “OPEN” .
Proceed to Test Step 8.
(continued)
178 UENR0612-07
Circuit Tests
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