FILTER & LINES GP-ENGINE OIL 3967781 - Caterpillar

Machine ECM
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the system voltage circuit of the machine.
Table 1
Machine ECM (MID 39)
DTC Code Description System Response
168-3 Electrical System: Voltage Above Normal The ECM activates this diagnostic code when the system voltage is above 32.0 VDC. Starter motor will not be allowed to engage.
168-4 Electrical System: Voltage Below Normal The ECM activates this diagnostic code when the system voltage is below 18.0 VDC. Starter motor will not be allowed to engage. Possible causes for an FMI 3 diagnostic code are:
The alternator output is above normal.
The harness wiring has failed.
The ECM has failed. This situation is unlikely.Possible causes for an FMI 4 diagnostic code are:
Machine not been used for an extended period with battery disconnect switch ON.
The alternator output is below normal.
The harness wiring has failed.
The ECM has failed. This situation is unlikely.
Illustration 1 g03748821
Schematic of the electrical power supply connections
Note: The diagram above is a simplified schematic of the connections for the system voltage 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 The System Voltage Circuit Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 4 diagnostic code, proceed to Test Step 3.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The System Voltage At The ECM
A. Turn key start switch and disconnect switch ON.
Start the engine and run the engine at high idle. If FMI 3 code is active prior to engine start, starter motor will not be allowed to engage. In this case, transition the key to the RUN position.
B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with battery power.
Check the ECM connector for the correct torque of 6 N m (53 lb in).
Check the harness for abrasion and for pinch points from the battery to the ECM, and from the keyswitch to the ECM.
C. At the machine harness connector for the ECM, insert a 7X-1710 Multimeter Probe along the contact for the power supply (J1-31 or J1-39). Insert the other probe along the return contact (J1-13, J1-23, or J1-57). Measure the voltage. Voltage is between 22.0 VDC and 28.0 VDC. OK - Voltage is between 22.0 VDC and 28.0 VDC.
Proceed to Test