HOUSING-ACCESSORY DRIVE 8N8300 - Caterpillar

Transmission ECM
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the electrical power supply circuits of the machine.
Table 2
Transmission ECM (MID 81)
DTC Code Description System Response
168-2 Electrical System Voltage: Data Erratic, Intermittent, or Incorrect All new sensor diagnostic codes are disabled after this event goes active. Any old sensor diagnostic codes will remain active until this event is cleared.
168-3 Electrical System Voltage: Voltage Above Normal The ECM activates this diagnostic code when the system voltage is above 32.0 VDC.
168-4 Electrical System Voltage: Voltage Below Normal The ECM activates this diagnostic code when the system voltage is below 20.0 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.Possible causes for an FMI 2 Diagnostic code are:
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.Possible causes for an FMI 3 Diagnostic code are:
The sensor supply or the ground circuit in the machine harness is open.
The signal circuit in the machine harness is shorted to another circuit.
The signal circuit in the machine harness is open or the sensor is disconnected.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.Possible causes for an FMI 4 Diagnostic code are:
The signal circuit in the machine harness is shorted to ground.
The sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.
Illustration 2 g06004376
Schematic of the Power Supply circuits
Note: The diagram above is a simplified schematic of the connections for the Power Supply 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, UENR6729 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 3
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With The System Voltage Circuit
Code present. FMI 2 diagnostic code, proceed to Test Step 2.
FMI 3 diagnostic code, proceed to Test Step 3.
FMI 4 diagnostic code, proceed to Test Step 6.
Begin Process For FMI 2 Troubleshooting HERE
2. Test The Battery
A. Turn Key start switch to the ON position.
B. Observe the status of the diagnostic code.
The diagnostic code is NOT active.