The following is a list of diagnostic codes (DTCs) that are associated with the relay circuits of the machine.
Machine ECM (MID 39) | |||
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J1939 | CDL | Code Description | System Response |
444-3 | Starter Motor Relay: Voltage Above Normal | Unable to crank the engine of the machine.
Starter will overheat. |
|
444-5 | Starter Motor Relay: Current Below Normal | Unable to crank the engine of the machine. | |
444-6 | Start Motor Relay: Current Above Normal | Unable to crank the engine of the machine. | |
3467-6 | Main Power Relay: Current Above Normal | The voltage is outside of the acceptable range, machine will not operate. |
A relay is a component that uses a small amount of electrical current to control the state of a circuit. The circuit is either opened or closed.
Illustration 1 | g06495752 |
Schematic of the relay circuits |
Note: The preceding diagram is a simplified schematic of the connections for the relays. The schematic is electrically correct. However, not all 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
Required Tools | |||
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Tool | Part Number | Description | Qty |
T1 | 146-4080(1) | Digital Multimeter Group | 1 |
8T-3224 | Needle Tip Group | 1 | |
7X-1710 | Multimeter Probe Group | 1 | |
8T-8726 | Cable Assembly (Three Pin) (3-Pin Breakout) | 1 | |
T2 | JERD2129 | Cat® Electronic Technician (Cat ET) | 1 |
Windows-based PC | 1 | ||
538-5051 | Communication Adapter Gp | 1 | |
T3 | 6V-4148 | Connector Repair Kit (Sure Seal) | 1 |
T4 | 190-8900 | Connector Field Repair Kit (Deutsch) | 1 |
T5 | 175-3700 | Connector Repair Kit Deutsch DT | 1 |
(1) | This multimeter can use an RS232C cable to connect to a Laptop computer or Dataview tool gp for troubleshooting. |
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.
- 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 3 diagnostic code, proceed to "FMI 3".
- FMI 5 diagnostic code, proceed to "FMI 5".
- FMI 6 diagnostic code, proceed to "FMI 6".
Check The Machine Harness For A Short | ||
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Troubleshooting Test Steps | Values | Results |
1. Turn the key start switch and disconnect switch to the OFF position. 2. Disconnect the relay from the harness. 3. Disconnect the ECM machine harness connectors. 4. At the ECM machine harness connector, measure the resistance between the signal contact and all other contacts that are used in the ECM. |
Each resistance measurement is greater than 5KΩ. | Result: All resistance measurements are greater than 5K Ω. Proceed to "Check If The Diagnostic Code Remains" Table 4. Result: One or more readings are less than 5 Ω. Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness. Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit. Proceed to "Check If The Diagnostic Code Remains" Table 4. |
Check If The Diagnostic Code Remains | ||
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Troubleshooting Test Steps | Values | Results |
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch to the ON position. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock. 6. Check if the diagnostic code is active. |
The diagnostic code is no longer present. | Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. For more information refer to the "ECM - Replace" section if the ECM needs to be replaced. STOP. |
Check The Relay | ||
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Troubleshooting Test Steps | Values | Results |
1. Turn the key start switch and disconnect switch to the OFF position. 2. Disconnect the relay from the wiring harness. 3. At the machine harness connector for the relay, place a jumper wire between the signal wire and the signal return. 4. Turn the key start switch and the disconnect switch to the ON position. Do not start the engine. 5. Observe the status of the diagnostic code. |
The diagnostic code changes from an FMI 5 to an FMI 6 after the jumper wire is installed. | Result: The harness is correct. The diagnostic code changes from an FMI 5 to an FMI 6 after the jumper wire is installed. The relay has failed. Repair - Replace the relay. Proceed to "Check If The Diagnostic Code Remains" 7. Result: The diagnostic code remains active. Proceed to "Check The Harness For An Open" Table 6. |
Check The Harness For An Open | ||
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Troubleshooting Test Steps | Values | Results |
1. Turn key start switch and disconnect switch to the OFF position. 2. Disconnect the machine harness connectors from the ECM. 3. The jumper wire remains installed. 4. At the ECM machine harness connector, measure the resistance between the signal contact and the return contact. |
The resistance is less than 5 Ω. | Result: The resistance is less than 5 Ω. The machine harness is correct. Proceed to "Check If The Diagnostic Code Remains" 7. Result: The resistance is greater than 5 Ω. The resistance measurement is not correct. There is an open circuit in the machine harness. Repair: Repair or replace the machine harness. Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit. Proceed to "Check If The Diagnostic Code Remains" 7. |
Check If The Diagnostic Code Remains | ||
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Troubleshooting Test Steps | Values | Results |
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch to the ON position. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock. 6. Check if the diagnostic code is active. |
The diagnostic code is no longer present. | Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. For more information refer to the "ECM - Replace" section if the ECM needs to be replaced. STOP. |
Check The Relay | ||
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Troubleshooting Test Steps | Values | Results |
1. Turn the key start switch and disconnect switch to the ON position. 2. Observe the status of the diagnostic code. 3. Disconnect the relay from the machine harness. |
The FMI 6 changes to FMI 5 when the relay is disconnected. | Result: FMI 6 changes to FMI 5 when the relay is disconnected. The harness is correct. The relay has failed. Repair: Repair or replace the relay. Proceed to "Check If The Diagnostic Code Remains" Table 10. Result: The diagnostic code remains active. Proceed to "Check The Return Circuit For A Short To Ground" Table 9. |
Check The Return Circuit For A Short To Ground | ||
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Troubleshooting Test Steps | Values | Results |
1. Turn key switch and disconnect switch to the OFF position. 2. The relay remains disconnected from the machine harness. 3. Disconnect the machine harness connectors from the ECM. 4. At the ECM machine harness connector, measure the resistance between the signal contact and all other contacts that are used in the ECM. |
Each resistance measurement is greater than 5K Ω. | Result: Each resistance measurement is greater than 5K Ω. The machine harness is correct. Proceed to "Check If The Diagnostic Code Remains" Table 10. Result: Each resistance measurement is not greater than 5K Ω. A short circuit exists between the signal circuit and the circuit with the low-resistance measurement. Repair: Repair or replace the machine harness. Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit. Proceed to "Check If The Diagnostic Code Remains" Table 10. |
Check If The Diagnostic Code Remains | ||
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Troubleshooting Test Steps | Values | Results |
1. Reconnect all harness connectors. Return machine to normal operating condition. 2. Turn the key start switch and the disconnect switch to the ON position. 3. Clear all diagnostic codes. 4. Operate the machine. 5. Stop the machine and engage the safety lock. 6. Check if the diagnostic code is active. |
The diagnostic code is no longer present. | Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP. Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. For more information refer to the "ECM - Replace" section if the ECM needs to be replaced. STOP. |