621K OEM Wheel Tractor-Scraper Sensor Supply

Table 1
Implement ECM (MID 82)
DTC	Description	System Response
41-3	8 VDC Supply : Voltage Above Normal	Sensors powered by the 8V supply will not function properly.
41-4	8 VDC Supply : Voltage Below Normal	Sensors powered by the 8V supply will not function properly.
1482 - 3	10 VDC Supply : Voltage Above Normal	Sensors powered by the 10V supply will not function properly.
1482 - 4	10 VDC Supply : Voltage Below Normal	Sensors powered by the 10V supply will not function properly.

Transmission/Chassis ECM

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Table 2
Transmission/Chassis ECM (MID 27)
DTC	Description	System Response
41 - 3	8 V Supply : Voltage Above Normal	Sensors powered by the 8 VDC supply will not function properly.
41 - 4	8 V Supply : Voltage Below Normal	Sensors powered by the 8 VDC supply will not function properly.
262-3	5 V Supply : Voltage Above Normal	Sensors powered by the 5 VDC supply will not function properly.
262-4	5 V Supply : Voltage Below Normal	Sensors powered by the 5 VDC supply will not function properly.
1482 - 3	10 V Supply : Voltage Above Normal	Sensors powered by the 10 VDC supply will not function properly.
1482 - 4	10 V Supply : Voltage Below Normal	Sensors powered by the 10 VDC supply will not function properly.

Seat ECM

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Table 3
Seat ECM (MID 314)
DTC	Description	System Response
520708-3	Sensor Power Supply : Voltage Above Normal	Modules powered by the 24 VDC supply will not function properly.
520708-6	Sensor Power Supply : Current Above Normal	Modules powered by the 24 VDC supply will not function properly.

Suspension System ECM

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Table 4
Suspension System ECM (MID 315)
DTC	Description	System Response
520708-3	Sensor Power Supply : Voltage Above Normal	Modules powered by the 24 VDC supply will not function properly.
520708-6	Sensor Power Supply : Current Above Normal	Modules powered by the 24 VDC supply will not function properly.

Possible Causes and Schematics

The diagnostic code is recorded when the interface module indicates that the voltage of the sensor supply circuit is too high, too low, or erratic.

Possible causes of an FMI 3 diagnostic code are:

The output of the sensor supply has shorted to the +battery circuit.
The ECM has failed. A failure of the ECM is unlikely.

Possible causes of an FMI 4 diagnostic code are:

The output of sensor supply has an open circuit.
A sensor has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible causes of an FMI 06 Diagnostic code are:

The sensor supply output is shorted to ground.
A sensor in the power supply circuit has failed.
The ECM may have failed. This situation is unlikely.

Note: Before performing this procedure, verify that all circuit breakers and all fuses in the charging circuit and the ECM system supply circuit are closed. If a problem with a circuit breaker or a fuse is found, correct the problem, and check for codes before proceeding with the following steps.

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Illustration 1	g03316830
Schematic of the 5 VDC Sensor Supply Voltage for the Transmission/Chassis ECM

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Illustration 2	g03414897
Schematic of the 8 VDC Sensor Supply Voltage for the Transmission/Chassis ECM

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Illustration 3	g03316831
Schematic of the 10 VDC Sensor Supply Voltage for the Transmission/Chassis ECM

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Illustration 4	g03347928
Schematic of the 8 VDC Sensor Supply Voltage for the Implement ECM

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Illustration 5	g03347931
Schematic of the 10 VDC Sensor Supply Voltage for the Implement ECM

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Illustration 6	g03502425
Schematic of the sensor supply voltage connections for the Seat ECM

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Illustration 7	g03502427
Schematic of the sensor supply voltage connections for the Cushion Hitch ECM

Note: The diagrams above are simplified schematics of the Transmission/Chassis ECM, Implement ECM, and other ECM connections. The diagrams are electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, KENR9577 for the complete schematic of the 621K.

Troubleshooting Procedure

Note: Poor harness connections are often the cause of a problem in electrical circuits. Before performing any troubleshooting procedure, inspect all of the connectors involved in the circuit. Verify that all of the connections in the circuit are dry, clean, secure, and in good condition. Each pin and socket in the connectors should mate correctly when the connectors are fastened together. Check for exposed wires at the connectors for nicks or abrasion. If a problem is found with any of the connections: correct the problem and verify that diagnostic code is still active, before performing the following procedures. For more information, refer to Troubleshooting, "Electrical Connector - Inspect".

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Table 5
Troubleshooting Test Steps	Values	Results
1. Identify The Active FMI Code Associated With The Sensor Supply Circuit	Code present	FMI 3 diagnostic code, proceed to Test Step 2. FMI 4 diagnostic code, proceed to Test Step 5. FMI 6 diagnostic code, proceed to Test Step 9.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Sensor Supply Voltage At The Sensors. A. Turn the key start switch and the disconnect switch ON. B. Disconnect the machine harness connector from the sensors. C. At the machine harness connector for the sensors, measure the voltage between the voltage supply contact and the voltage return contact.	Voltage is 5.0 ± 0.3 VDC, 8.0 ± 0.5 VDC, or 10.0 ± 0.95 VDC. For Seat ECM and Suspension System ECM, see schematic for expected voltage.	OK - The voltage is appropriate for the circuit as determined by the schematic. Verify that the diagnostic code is present. If the code is still active, go to Test Step 4. NOT OK - The reading is NOT the appropriate voltage as determined by the schematic. The voltage is greater than the expected voltage for the circuit based on the schematic. The sensor supply voltage is NOT correct. Proceed to Test Step 3.
3. Check The Voltage At The ECM. A. Turn the key start switch and the battery disconnect switch to the OFF position. B. At the machine harness connector for the ECM, insert a 7X-1710 Multimeter Probe along the contact for the sensor power. Insert another probe along the return contact for the sensor power. C. Turn the disconnect switch and key start switch to the ON position. D. Perform a wiggle test. Observe the voltage measurement for the multimeter and wiggle the machine harness connectors of the ECM. Gently pull on the wires and move the wires around.	Voltage is 5.0 ± 0.3 VDC, 8.0 ± 0.5 VDC, or 10.0 ± 0.95 VDC. For Seat ECM and Suspension System ECM, see schematic for expected voltage.	OK - The voltage is appropriate for the circuit as determined by the schematic. Proceed to Test Step 4. NOT OK - The voltage measurement is unstable. The voltage measurement is showing a large amount of variation. The manipulation of the machine harness and connectors does not affect the measurement. Repair- Replacement of the ECM may be required. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. STOP NOT OK - The voltage measurement is stable and within the specified range. However, the measurement between the ECM (+) and the ECM (-) contacts are not stable or in the correct range at all times. Refer to Troubleshooting , "ECM - Replace" if the ECM needs to be replaced. Repair- The wiggle test has revealed a possible short circuit or grounded circuit. Inspect the wiring harness for damage. Inspect the harness connectors for corrosion or loose connections. Use the information gathered from the wiggle test to identify the faulty wire connection. STOP
Begin Process For FMI 4 Troubleshooting HERE
5. Check The Supply Circuits At The ECM. A. Turn the key start switch and the disconnect switch OFF. B. Remove the voltage supply and return wires from the ECM harness for the related supply circuit. C. At the contacts for the related voltage supply and return circuit, measure the voltage.	Voltage is 5.0 ± 0.3 VDC, 8.0 ± 0.5 VDC, or 10.0 ± 0.95 VDC.	OK - The voltage is appropriate for the circuit as determined by the schematic. Install the voltage supply and return wires back into the harness. Proceed to Test Step 6. NOT OK - The voltage measurement is not correct. The ECM power supply is not correct. Repair- The ECM may need replaced. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. Refer to Troubleshooting , " ECM - Replace " if the ECM needs to be replaced. STOP
6. Check The Sensors. A. Turn key start switch and disconnect switch ON. B. One at a time, disconnect the sensors from the machine harness. C. After disconnecting each sensor, check the status of the diagnostic code.	The diagnostic code is no longer active.	OK - The diagnostic code is not active when one of the sensors is disconnected. The harness circuit is correct. The sensor that was most recently been disconnected has failed. Repair - Replace the sensor in question. Verify that the new sensor has corrected the problem. NOT OK- The diagnostic code remained active. Proceed to Test Step 7.
7. Check The Sensor Supply Voltage At The Sensors. A. Turn the key start switch and the disconnect switch ON. B. Disconnect the machine harness connector from the sensors. C. At the machine harness connector for the sensors, measure the voltage between the voltage supply contact and the voltage return contact.	Voltage is 5.0 ± 0.3 VDC, 8.0 ± 0.4 VDC, or 10.0 ± 0.95 VDC.	OK - The voltage is appropriate for the circuit as determined by the schematic. Verify that the diagnostic code is present. If the code is still active, go to Test Step 11. STOP NOT OK - The reading is NOT the appropriate voltage as determined by the schematic. The voltage is greater than the expected voltage for the circuit based on the schematic. The sensor supply voltage is NOT correct. Proceed to Test Step 8.
8. Check For A Short Circuit In The Machine Harness. A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the sensors from the machine harness one at a time. Disconnect the machine harness connectors from the ECM. C. Measure the resistance from the voltage supply wire to all other contacts in the harness.	The resistance readings are greater than 5K Ω.	OK - The resistance is greater than 5K Ω. The harness circuit resistance is correct. Proceed to Test Step 11. NOT OK - Resistance is less than 5 Ω. The supply wire is shorted to whichever resistance measurements were low. Repair: Repair or replace the machine harness. Confirm that the harness repair or replacement has corrected the problem. If the diagnostic code is present after harness repair or replacement, replacement of the ECM may be necessary. 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.
Begin Process For FMI 6 Troubleshooting HERE
9. Check For A Short To Ground A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the machine harness from the ECM. C. At the ECM harness connector, measure the resistance between frame ground and the contact for the supply of the sensor.	The resistance is greater than 5K Ω.	OK - The harness circuit resistance is correct. Verify that the diagnostic code is present. Repair: Perform this procedure again. Also, recheck if the diagnostic code is active. Proceed to Test Step 11. NOT OK - The resistance is less than 5 Ω. The machine harness or a sensor has failed. 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 Test Step 10.
10. Disconnect Each Sensor And Check For A Short To Ground. A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the sensors from the machine harness one at a time. C. After a sensor is disconnected, check the resistance from frame ground to sensor supply of the machine harness connector for the ECM. D. Repeat for each sensor.	The resistance is greater than 5K Ω.	OK - The resistance is greater than 5K Ω. The harness circuit resistance is correct. The sensor that was last disconnected has failed. Repair: Replace the sensor that caused the short. Confirm that the replacement sensor has corrected the problem. If the diagnostic code is present after sensor replacement. Confirm that replacing the sensor has corrected the machine problem. Proceed to Test Step 11. NOT OK - Resistance is less than 5 Ω after all the sensors have been disconnected from the machine harness. The machine harness is shorted to ground. Repair: Repair or replace the machine harness. Confirm that the harness repair or replacement has corrected the problem. If the diagnostic code is present after harness repair or replacement, replacement of the ECM may be necessary. Note: A resistance greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement greater than 5K Ω would indicate an open in the circuit. Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time. Refer to Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. Proceed to Test Step 11.
11. Check If The Diagnostic Code Remains A. Turn the key start switch and the disconnect switch ON. B. Clear all diagnostic codes. C. Operate the machine. D. Stop the machine and engage the parking brake. E. Check if diagnostic code is active.	Code for supply voltage is NO longer present.	OK - No active diagnostic code. The problem does not exist at this time. The initial diagnostic code may have been caused by a poor electrical connection or a short at one of the tested harness connectors. Resume normal machine operation. NOT OK - Perform this procedure again. Verify that the measurements for the alternator are correct. Verify that the system voltage circuit connections are in good condition and verify that the system voltage circuit connections are tight. Repair- If the problem remains and no cause can be found, the ECM may have failed. A failed ECM is unlikely. Prior to replacing the ECM, contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced. STOP