HOSE AS 4377371 - Caterpillar

Illustration 1 g03818737
Switch controlled solenoid connections
Note: The diagram above is a simplified schematic of the Machine ECM connections. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of Electrical Schematic, UENR0013 (963K) Electrical Schematic, UENR4163 (953K) for the complete schematic.Diagnostic Trouble Code Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. Check the wiring harness for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure.
Identify the active FMI code associated with the components.
Determine which code is present and use the list below to determine which procedure to follow.
FMI 3 diagnostic code, proceed to Table 2.
FMI 6 diagnostic code, proceed to Table 3.
Table 2
FMI 3 Troubleshooting
Troubleshooting Test Steps Values Results
1. Check The Switch
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the switch from the machine harness. Place the switch in the UNLOCKED position.
C. At the back of the switch, measure the resistance between contacts "B" and "C"
The resistance measurement is less than 5 Ω. OK - The resistance measurement is less than 5 Ω. The switch is operating properly.
Proceed to Test Step 2.
NOT OK - The resistance measurement is greater than 5K Ω. The switch has failed.
Repair: Repeat this Test Step to verify that the switch has failed. Toggle the switch state while observing the resistance measurement. If the resistance measurement is greater than 5K Ω, the switch has failed. Replace the switch.
Proceed to Test Step 4.
2. Check The Signal Circuit For An Open
A. The key start switch and the disconnect switch remain in the OFF position.
B. Disconnect the machine harness connectors from the ECM and remove the relay.
C. Reconnect the switch to the machine harness. Place the switch in the UNLOCKED position.
D. At the ECM harness connector inserts a multimeter probe at the switch signal wire contact.
E. At the harness connector for the relay, insert a multimeter probe at the relay coil contact.
F. Measure the resistance between the signal contact and relay coil contact.
The resistance measurement is less than 5 Ω. OK - The resistance measurement is less than 5 Ω. The wiring harness is correct.
Proceed to Test Step 3.
NOT OK - The resistance measurement is greater than 5K Ω. There is an open in the harness.
Repair: Repair or replace the machine harness.
Proceed to Test Step 4.
3. Check The Signal Circuit For A Short
A. The key start switch and the disconnect switch remain in the OFF position.
B. The ECM harness connectors and relay remain disconnected.
C. At the ECM harness connector, measure the resistance between the switch signal circuit and all the other contacts that are used in the