MOTOR AS 1474835 - Caterpillar

Machine ECM 2
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the operator control switch to battery of the machine.
Table 5
Machine ECM 2(MID 432)
DTC Code Description System Response
1393-4 Output Driver Enable Line: Voltage Below Normal ATT STEM 1 Retract PRV will not function Possible causes for an FMI 4 Diagnostic code are:
The signal contacts are open.
The fuse has failed.
The ECM has failed. A failure of the machine ECM is unlikely.
Illustration 3 g06310454Note: The diagram above is a simplified schematic of the connections for the operator control switch (switch to battery) circuits. 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. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure. For sensors powered via the fuse panel, check the condition of the appropriate fuse before beginning the 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 4 diagnostic code, proceed to Table 6.
Table 6
FMI 4 Troubleshooting
Troubleshooting Test Steps Values Results
1. Check the Harness For an Open
A. Turn key start switch and disconnect switch OFF.
B. Disconnect the switch from the machine harness.
C. Disconnect the J1 and J2 machine harness connector.
D. At the machine harness connector for the switch, place a jumper wire between the signal contacts.
E. At the machine harness connect for the ECM, measure the resistance between the signal contacts.
The resistance is less than 5 Ω. OK - The circuit is correct.
Proceed to Test Step 2.
NOT OK - The resistance is greater than 5K ohms . The circuit is open.
Repair: Repair or replace the machine harness.
Note: A resistance that is greater than 5 Ω but less than 5K ohms indicates a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω indicates an open in the circuit.
Proceed to Test Step 5.
2. Check The Circuit For A Short
A. Turn the key start switch and disconnect switch OFF.
B. Disconnect the switch from the machine harness.
C. Disconnect the J1 and J2 machine harness connections from the machine ECM.
C. At the machine harness connector for the ECM, measure the resistance between each of the signal contacts to every other contact used in the J1 and J2 machine harness connectors.
The resistance is greater than 5K Ω. OK - The resistance is correct.
Proceed to Test Step 3.
NOT OK - The resistance check is not correct.
Repair: There is a short in the signal circuits of the machine harness. Repair or replace the