HOUSING AS-DRIVE 5T0374 - Caterpillar

Machine ECM
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the solenoid return of the machine.
Table 1
Machine ECM (MID 39)
DTC Code Description System Response
1674-3 Solenoid Return #1: Voltage Above Normal The park brake solenoid will not function properly.
1674-6 Solenoid Return #1: Current Above Normal The park brake solenoid will not function properly. Possible Causes for an FMI 3 diagnostic code are:
The return circuit of the solenoid is shorted to another voltage source.
The ECM has failed. A failure of the ECM is unlikely.Possible causes for an FMI 6 diagnostic code are:
The return circuit for the solenoid is shorted to a ground source.
The ECM has failed. A failure of the ECM is unlikely.
Illustration 1 g03756718
Schematic of the solenoid return connections
Note: The diagram above is a simplified schematic of the connections for the solenoid return connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the electrical schematic for the specific machine being serviced 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 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 this diagnostic code is active before performing a troubleshooting procedure.
Table 2
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With Solenoid Circuit
Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 6 diagnostic code, proceed to Test Step 4.
2. Check The Return Circuit Of The Solenoid For A Short
A. Turn the key start switch and the disconnect switch OFF.
B. Disconnect the harness connection at solenoid.
C. Disconnect J1 and J2 connectors from ECM.
D. At the machine harness connectors for the ECM, measure the resistance between the return contact of the solenoid and each of the other circuits that are used in the J1 and J2 connectors for the ECM.
Each reading is greater than 5K Ω. OK - All resistance readings are greater than 5K Ω .
Proceed to Test Step 3.
NOT OK - One or more readings are less than 5 Ω.
Repair: A short exists between the return contact and the circuit with the low resistance.
Note: For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.
Proceed to Test Step 5.
3. Check The Operation Of The ECM
A. At the machine harness connector for the ECM, use a removal tool to remove the return wire from the harness connector.
B. Reconnect the machine harness J1 and J2 connectors to the ECM.
C. Turn the disconnect switch and the key start switch to the ON position.
D. Observe the status of the active diagnostic