BRACKET 3643406 - Caterpillar

Illustration 1 g01885233
Schematic of the secondary steering relay
This diagnostic code is associated with the "Secondary Steering" relay. The FMI 5 diagnostic code is recorded when the electronic control module (ECM) reads the current of the relay as below normal (Open circuit).The possible causes of this diagnostic code are listed below:
The energizer circuit of the relay is open.
The return circuit of the relay is open.
The relay has failed.
The ECM has failed. A failure of the ECM is unlikely.Note: The following test procedure may create other diagnostic codes. Clear these diagnostic codes when the problem has been corrected. Ensure that the diagnostic code of CID 420 FMI 5 is active before performing this procedure.Note: Use a calibrated digital multimeter for the measurements in this procedure.System Response:The system for the secondary steering will not energize.Test Step 1. CHECK THE RELAY.
Turn the disconnect switch and the key start switch to the ON position.Note: Do not start the engine. Ensure that the diagnostic code for the relay is active.
Disconnect the machine harness from the relay.
At the machine harness connector for the relay that is being tested, install a jumper wire.
Install a jumper wire from the signal wire (U738-PU(Purple)) to the return wire (H867-YL(Yellow)).
Observe the status of the diagnostic code. The diagnostic code is active or the diagnostic code is not active.Expected Result:The status of the diagnostic code is active and the status of the diagnostic code is not active as the jumper is installed and then removed.Results:
OK - The circuit is correct.Repair: The relay has failed. Repeat the Test Step "CHECK THE RELAY" and verify that the relay failed. Replace the relay.STOP
NOT OK - The diagnostic code remains active. Proceed to Test Step 2.Test Step 2. CHECK THE RELAY CIRCUIT FOR AN OPEN.
The jumper between the signal wire and the return wire remains installed.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector J2 from the ECM.
At the J2 machine harness connectors for the ECM, measure the resistance from contact "J2-2" (U738-PU(Purple)) for the relay to contact "J2-4" (return contact).Expected Result:There should be continuity (less than 5.0 ohms resistance).Results:
OK - The machine harness is correct. Proceed to Test Step 3.
NOT OK - There is an open circuit in the machine harness.Repair: The open circuit is in the signal wire (U738-PU(Purple)) or in return wire (H867-YL(Yellow)) of the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Perform the following:
Visually inspect the harness connectors.
Clean the contacts of the harness connectors.
Visually inspect the insulation of the wires for damage that is caused by excessive heat, battery acid, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Reconnect all harness connectors. Verify the following:
Connectors are fully seated.
The clips for each connector are fastened securely.
Turn the disconnect switch and the key start switch to the ON position.
Clear all the inactive diagnostic codes.
Operate the machine.
Stop the machine and place the parking brake switch