SEAL 7T7451 - Caterpillar

Illustration 1 g02653161
Connections of the Implement (Hydraulic) Lockout Switch
The Implement Lockout Switch provides two "switch to ground" inputs to the Implement ECM. The common ground circuit C214-BK(Black) for the switch is provided from the Implement ECM.If the ECM detects that neither switch circuit is grounded, the ECM will disable implement control. The ECM will activate a CID 0490 FMI 04 diagnostic code for voltage, in this case ground, below normal.The possible causes of this diagnostic code are listed below:
The switch has failed.
One or both of the switch inputs is shorted to ground.
The ECM has failed. This condition is unlikely.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Test Step 1. CHECK THE SWITCH
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is active.
Observe the status of the diagnostic code while the connector of the switch is disconnected from the machine harness. Reconnect the switch and disconnect the switch again. Observe the status of the diagnostic code. Expected Result:The active CID 0490 FMI 04 diagnostic code remains the same when the switch is disconnected. Results:
OK - The CID 0490 FMI 04 diagnostic code remains the same . Proceed to Test Step 2.
NOT OK - The CID 0490 FMI 04 diagnostic code is NO longer active. A CID 0490 FMI 03 diagnostic code becomes active when the connector of the switch is disconnected. The machine harness and the ECM are operating correctly. The switch has failed.Repair: Replace the switch. After replacement of the switch, verify that the operation of the new switch is correct before operating the machine. STOPTest Step 2. CHECK THE SWITCH CIRCUITS FOR A SHORT TO GROUND
Turn the key start switch and the disconnect switch to the OFF position. The implement lockout switch remains disconnected from the machine harness.
Disconnect the J1 machine harness connector from the Implement ECM.
At machine harness connector J1 for the Implement ECM, perform the following:
Measure the resistance between contact J1-33 (wire E917-WH(White)) and frame ground.
Measure the resistance between contact J1-33 (wire E917-WH(White)) and each of the other circuits that are used for the Implement ECM.
At machine harness connector J1 for the Implement ECM, perform the following:
Measure the resistance between contact J1-34 (wire E918-GN(Green)) and frame ground.
Measure the resistance between contact J1-34 (wire E918-GN(Green)) and each of the other circuits that are used for the Implement ECM.Expected Result:Each measurement is greater than 5000 ohms.Results:
OK - Each measurement is greater than 5000 ohms. The resistance of the switch circuit does not indicate a short in the machine harness. Proceed to Test Step 3.
NOT OK - One or more resistances are less than 5000