FRAME ASSEM. 2G4926 - Caterpillar

Implement ECM
The following is a list of codes that are associated with the system voltage circuit of the Implement ECM.
Table 1
Implement ECM
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.
168-4 Electrical System Voltage : Below Normal The ECM activates this diagnostic code when the system voltage is below 18.0 VDC. Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections may 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.The FMI 2 error code will only be logged under the following conditions:
Three voltage readings that are below 18 VDC or above 32 VDC in a period of 7 seconds.
The key switch is in the ON position.
The engine is running.
The engine is not cranking.Possible Causes for an FMI 2 diagnostic code are:
A poor circuit connection to the system ground.
A poor circuit connection to system voltage.
A charging system component has failed.
Intermittent connection in the battery circuit for the ECM.
The ECM has failed. A failure of the ECM is unlikely.The FMI 3 error code will be logged when the system voltage is greater than 32.0 VDC. System electronics may be damaged if the voltage remains high for an extended time.Possible Causes for an FMI 3 diagnostic code are:
The alternator output is above normal.
Jump starting (hooking the machine to an outside source of power).
The ECM has failed. A failure of the ECM is unlikely.The FMI 4 error code will be logged when the system voltage is less than 18.0 VDC.Possible Causes for an FMI 4 diagnostic code are:
A charging system component has failed.
The harness wiring has failed.
The ECM fuse at the fuse panel is open.
The machine is at low idle and there is excess load to the alternator.
The alternator output is below normal.
The ECM has failed. A failure of the ECM is unlikely.
Illustration 1 g03594914
J1 Implement Electrical Power Supply Connections
Note: The diagram above is a simplified schematic of the electrical circuit. 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 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.
Table 2
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With The