The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the electrical power supply circuits of the machine.
| Implement ECM (MID 82) | ||
|---|---|---|
| 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 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.
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 1 | g03592698 |
|
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, UENR3117 for the complete schematic.
The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the electrical power supply circuits of the machine.
| 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 | g03592700 |
|
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, UENR3117 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.
| 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. |
OK - The diagnostic code is NOT active. Proceed to Test Step 8. NOT OK - The diagnostic code is active. Repair: See Special Instruction, SEHS7633, "Battery Test Procedure". Proceed to Test Step 8. |
| Begin Process For FMI 3 Troubleshooting HERE | ||
| 3. Check The Charging System A. Turn key start switch and disconnect switch ON. B. Observe the status of the diagnostic code. |
Diagnostic code remains active. |
OK - The diagnostic code remains active. Proceed to Test Step 5. NOT OK - The diagnostic code is no longer active. Proceed to Test Step 4. |
| 4. Check The Charging System A. Start the engine. B. Observe the status of the diagnostic code. |
Diagnostic code is active. |
OK - Diagnostic code is active. Repair: The charging system is charging at an excessive voltage. Check the charging system. See Special Instruction, SEHS0354, "Charging System Troubleshooting". Proceed to Test Step 5. NOT OK - Diagnostic code is not active. Repair: There is no problem at this time. Watch for a recurrence. Proceed to Test Step 8. |
| 5. Check The Battery Voltage A. The engine is stopped. At the battery, measure the voltage. |
The voltage is less than 16 VDC. |
OK - The voltage is less than 16 VDC. Repair: Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the ECM may have failed. Prior to replacing to the ECM, contact the local dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Troubleshooting, "ECM - Replace". Proceed to Test Step 8. NOT OK - The voltage is not less than 16 VDC. Repair: The charging system is charging at an excessive voltage. Check the charging system. See Special Instruction, SEHS0354, "Charging System Troubleshooting". Proceed to Test Step 8. |
| Begin Process For FMI 4 Troubleshooting HERE | ||
| 6. Check The Battery Voltage A. Start the machine and run at high idle for several minutes. B. Measure the battery voltage at the battery posts. |
Battery voltage is greater than 9.0 VDC. |
OK - Battery voltage is greater than 9 VDC. Battery voltage is correct. Proceed to Test Step 7. NOT OK - Battery voltage is not greater than 9 VDC Repair: The charging system is not operating correctly. Check the charging system. See Special Instruction, SEHS0354, "Charging System Troubleshooting". STOP |
| 7. Check The Battery Voltage A. The engine must still be running at high idle. B. With the machine harness remaining connected, prepare to make a voltage measurement at the J1 connector at the ECM with a multimeter probe. C. At the machine harness for the ECM, insert the probe into the back of the J1 connector. Measure the voltage (VDC) between J1-31 and J1-13. |
Voltage is greater than 9.0 VDC. |
OK - Voltage is greater than 9 VDC. Battery voltage is correct. Proceed to Test Step 8. NOT OK - Voltage is not greater than 9 VDC. Repair: The machine harness is not correct. Repair the machine harness or replace the machine harness. Proceed to Test Step 8. |
| 8. Check If The Diagnostic Code Is Still Active A. Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, or chafing. B. Perform a C. Reconnect all harness connectors in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are fastened. D. Turn the disconnect switch and the key start switch to the ON position. E. Operate the machine. F. Determine if the diagnostic code is active. |
The diagnostic code is not active. |
OK - The diagnostic code is not active. The initial diagnostic code was probably caused by a poor electrical connection. The problem does not exist at this time. Resume normal machine operation. STOP NOT OK - The diagnostic code is active. The problem has not been corrected. Repair: Exit this procedure and perform the diagnostic code procedure again. If the problem persists, the ECM may have failed. Prior to replacing to the ECM, contact the local dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Troubleshooting, "ECM - Replace". STOP |