621K OEM Wheel Tractor-Scraper Solenoid Valve

Solenoid Valve - Test

621K OEM Wheel Tractor-Scraper [UENR5941]

621K OEM Wheel Tractor-Scraper Sensor Supply - Test

621K OEM Wheel Tractor-Scraper Switch Circuits - Test

HYDRAULIC SYSTEM

VALVE GP-SOLENOID

621K OEM Wheel Tractor-Scraper Solenoid Valve - Test

1.1. Implement ECM

2.1. Transmission/Chassis ECM

3.1. Possible Causes and Electrical Schematics

4.1. Troubleshooting Procedure

Implement ECM

The following is a list of codes that are associated with the solenoid valves associated with the Implement ECM.

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Table 1
Implement ECM (MID 82)
DTC	Description	System Response
358-3	Implement Pilot Pressure Supply Solenoid : Voltage Above Normal	The pilot pressure is used to engage/disengage the actuators of the implement system. A problem with the pilot solenoid results in a lack of control of multiple actuators.
358-5	Implement Pilot Pressure Supply Solenoid : Current Below Normal	The pilot pressure is used to engage/disengage the actuators of the implement system. A problem with the pilot solenoid results in a lack of control of multiple actuators.
358-6	Implement Pilot Pressure Supply Solenoid : Current Above Normal	The pilot pressure is used to engage/disengage the actuators of the implement system. A problem with the pilot solenoid results in a lack of control of multiple actuators.
1289-3	Cushion Hitch Solenoid : Voltage Above Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.
1289-5	Cushion Hitch Solenoid : Current Below Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.
1289-6	Cushion Hitch Solenoid : Current Above Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.
3835-3	Cushion Hitch Leveling Solenoid : Voltage Above Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.
3835-5	Cushion Hitch Leveling Solenoid : Current Below Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.
3835-6	Cushion Hitch Leveling Solenoid : Current Above Normal	The cushion hitch system is used to extend the cushion hitch cylinder. The machine accumulators are directed to increase the pressure and extend the cylinder. As the cylinder is fully extended, the hitch is raised. At full cylinder extension, the cushion hitch is now in the cushion ride mode. As loads are induced in the hitch system, the accumulators are used to absorb the energy to provide a cushioned ride.

Transmission/Chassis ECM

The following is a list of codes that are associated with the solenoid valves of the Transmission/Chassis ECM.

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Table 2
Transmission/Chassis ECM (MID 27)
DTC	Description	System Response
681-3	Park Brake Solenoid : Voltage Above Normal	With the solenoid energized to +battery, the operator will be unable to disengage the parking brake.
681-5	Park Brake Solenoid : Current Below Normal	When this diagnostic code is active, the ECM will be unable to control the parking brake solenoid. The parking brake will always be engaged.
681-6	Park Brake Solenoid : Current Above Normal	When this diagnostic code is active, the ECM will be unable to control the parking brake solenoid. The parking brake will always be engaged.
681-7	Park Brake Solenoid : Mechanical System Not Responding Properly	This FMI code is triggered when the park brake switch is moved to the OFF (disengage) position and the ECM does not detect a pressure of 2987 kPa (439 psi) or higher. This pressure level is required to release the parking brake within 10 seconds after the switch is used to disengage the brake. The most likely cause of this event code is a blockage in the hydraulic system. A blockage in the system will not allow for high enough pressure to release the brake. A mechanical problem could also allow for this code. Cold weather, approaching −32° C (−25° F) will change the oil viscosity and may keep the park brake from releasing.
740-3	Differential Lock Solenoid :Voltage Above Normal	The differential will be unlocked which can result in wheel slippage.
740-5	Differential Lock Solenoid : Current Below Normal	The differential will be locked which could result in a wheel dragging.
740-6	Differential Lock Solenoid : Current Above Normal	The differential will be unlocked which can result in wheel slippage.
1401-3	Transmission Solenoid 1 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1401-5	Transmission Solenoid 1 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1401-6	Transmission Solenoid 1 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1401-11	Transmission Solenoid 1 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1402-3	Transmission Solenoid 2 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1402-5	Transmission Solenoid 2 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1402-6	Transmission Solenoid 2 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1402-11	Transmission Solenoid 2 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1403-3	Transmission Solenoid 3 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1403-5	Transmission Solenoid 3 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1403-6	Transmission Solenoid 3 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1403-11	Transmission Solenoid 3 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1404-3	Transmission Solenoid 4 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1404-5	Transmission Solenoid 4 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1404-6	Transmission Solenoid 4 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1404-11	Transmission Solenoid 4 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1405-3	Transmission Solenoid 5 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1405-5	Transmission Solenoid 5 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1405-6	Transmission Solenoid 5 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1405-11	Transmission Solenoid 5 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1406-3	Transmission Solenoid 6 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1406-5	Transmission Solenoid 6 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1406-6	Transmission Solenoid 6 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1406-11	Transmission Solenoid 6 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
1407-3	Transmission Solenoid 7 : Voltage Above Normal	The transmission clutch is engaged and cannot be released. The machine will be locked out of gears that are unavailable due to the fault.
1407-5	Transmission Solenoid 7 : Current Below Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1407-6	Transmission Solenoid 7 : Current Above Normal	The transmission clutch is released and cannot be engaged. The machine will be locked out of gears that are unavailable due to the fault.
1407-11	Transmission Solenoid 7 : Failure Mode Not Identifiable	Transmission clutch engagements may be rough or slow in this condition. The machine will be locked out of gears that are unavailable due to the fault.
2742-3	Brake Accumulator Charging Solenoid : Voltage Above Normal	Brake pressure may fall below acceptable levels resulting in activation of event codes.
2742-5	Brake Accumulator Charging Solenoid : Current Below Normal	Brake pressure may fall below acceptable levels resulting in activation of event codes.
2742-6	Brake Accumulator Charging Solenoid : Current Above Normal	Brake pressure may fall below acceptable levels resulting in activation of event codes.

Possible Causes and Electrical Schematics

The solenoid is used to shutoff, release, distribute, or mix fluids on the machine. Generally, multiple solenoids are located together on a manifold. The solenoid converts electrical energy into magnetic energy, moving a spool located inside the housing of the valve. A spring is used to hold the spool in position until the solenoid is energized.

The magnetic force that acts on the valve spool is created when a coil inside the solenoid is energized.

Possible Causes for an FMI 3 Diagnostic code are:

The harness is shorted.
The ECM has failed. A failure of the ECM is unlikely.

Possible causes for an FMI 5 Diagnostic code are:

There is an open in the circuit.
The solenoid has failed.
The sensor was activated in Cat^® ET when the component is not on the machine.
The ECM has failed. A failure of the ECM is unlikely.

Possible causes for an FMI 6 Diagnostic code are:

A wire is shorted to ground.
The solenoid has failed.
The ECM has failed. A failure of the ECM is unlikely.

Possible causes for an FMI 7 Diagnostic code are:

The pressure of 2987 kPa (439 psi) was not realized within 10 seconds of disengaging the brake.
A blockage exists in the hydraulic system that has reduced the available pressure.
A mechanical issue exists that is not allowing the disengagement of the brake.
Extremely cold conditions exist that have changed the viscosity of the oil. Extreme cold is defined as −32° C (−25° F) or less.

Possible causes for an FMI 11 Diagnostic code are:

An internal failure of the interface module.

Possible causes for an FMI 13 Diagnostic code are:

The joystick may have been recently replaced and not calibrated or is not working properly.

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Illustration 1	g03348691
Implement ECM J1 and J2 solenoid connections

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Illustration 2	g03318064
Transmission/Chassis ECM J1 solenoid connections

Note: The diagrams above are simplified schematics of the ECM connections. The schematics are electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic for your specific machine. Refer to the list below to identify the correct schematic for your machine.

Electrical Schematic, UENR2689 for the 621K Tractor/Scraper.

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 3
Troubleshooting Test Steps	Values	Results
1. Identify Active FMI Code Associated With Solenoid Circuit	Code present.	FMI 3 diagnostic code, proceed to Test Step 2. FMI 5 diagnostic code, proceed to Test Step 4. FMI 6 diagnostic code, proceed to Test Step 7. FMI 7 diagnostic code, proceed to Test Step 10. FMI 11 diagnostic code, proceed to Test Step 12. FMI 13 diagnostic code, proceed to Test Step 13.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Machine Harness For A Short A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the harness connection at the solenoid. C. Disconnect the harness connection at the ECM. D. Measure the resistance of solenoid signal contact to all J1 and J2 connectors, if solenoid is wired directly to the ECM.	Each reading is greater than 5K Ω.	OK - All resistance readings are greater than 5K Ω. Proceed to Test Step 3. NOT OK - 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 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. STOP
3. Check The Operation Of The ECM A. The key start switch and the disconnect switch remain OFF. B. Use a wire removal tool to remove the solenoid signal wire from the wiring harness connector at the ECM. C. Reconnect the harness connection at the ECM. D. Turn the disconnect switch and the key start switch to the ON position.	The FMI 3 changes to an FMI 5 after the wire is disconnected.	OK - The FMI 3 changes to an FMI 5 after the wire is disconnected. The ECM has responded correctly to the condition of an open circuit. Reinstall the disconnected wire to the correct space in the ECM connector before proceeding to Test Step 9. Proceed to Test Step 9. NOT OK - The FMI 3 remains active. The status of the active diagnostic code did not change when the wire was disconnected from the ECM. Repair - The ECM has not responded correctly to the condition of an open circuit. The operation of the ECM is not correct. Prior to replacing the ECM, always contact the Technical Communication 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
Begin Process For FMI 5 Troubleshooting HERE
4. Check The Solenoid. A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the solenoid from the machine harness. C. Place a jumper wire between contact 1 and contact 2, at the harness connector for the solenoid. D. Turn the key start switch and the disconnect switch ON. Do not start the engine. E. As the jumper is removed and connected to the contacts, observe any code change.	The code changes to FMI 6 after the jumper wire is installed.	OK - The circuit is correct, the solenoid has failed. Repair: Replace the solenoid. After replacement of the solenoid, confirm the diagnostic code is not active. STOP NOT OK - The diagnostic code remains active. Proceed to Test Step 5.
5. Check The Machine Harness For An Open. A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the harness connectors from the ECM. C. The jumper wire from the previous step remains installed. D. At the machine harness connector for the ECM, measure the resistance at the ECM contacts for the solenoid.	The reading is less than 5 Ω.	OK - The reading is less than 5 Ω, the harness is correct. Proceed to Test Step 6. NOT OK - The reading is greater than 5K Ω. Circuit open in machine harness. Repair : The open is in the wire for the solenoid signal or the return wire for the solenoid. 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. STOP
6. Check The Operation of the ECM. A. Remove the jumper wire used in the last test step. B. At the connector for the ECM, use a wire removal tool to remove the signal wire from the ECM harness connector. C. Reconnect the machine harness connectors to the ECM. D. Turn the key start switch and the disconnect switch ON. Do not start the engine. E. Use a multimeter probe that is NOT connected to a multimeter or a similar device to connect with the ECM. Connect at the signal wire contact through the empty space. F. Observe the status of the diagnostic code. Ground the other end of the multimeter probe to frame ground.	The code changes to FMI 6 after the jumper wire is installed.	OK - The circuit is correct, the ECM has responded correctly to the condition of a grounded circuit. The operation of the ECM is correct. Reinstall the disconnected wire into the correct spot in the ECM connector before proceeding to Test Step 10. Proceed to Test Step 9. NOT OK - The diagnostic code remains an FMI 5 when the multimeter probe creates a short to ground. Repair: The ECM has not responded correctly to the condition of a grounded circuit. The operation of the ECM is not correct. Prior to replacing the ECM, always contact the Technical Communication 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
Begin Process For FMI 6 Troubleshooting HERE
7. Check The Solenoid. A. Turn the key start switch and the disconnect switch OFF. B. Disconnect the solenoid from the machine harness. C. Place a jumper wire between contact 1 and contact 2, at the harness connector. D. Turn the key start switch and the disconnect switch ON. Do not start the engine. E. As the jumper is removed and connected to the contacts, observe any code change.	The FMI 6 diagnostic code changes to an FMI 5 diagnostic code after the jumper wire is installed.	OK - The circuit is correct. The solenoid has failed. Repair: Repeat the jumper wire test. Verify the solenoid failure. Replace the solenoid. Note: After the solenoid is replaced, confirm that the diagnostic code is no longer active. STOP NOT OK - The diagnostic code remains active. Proceed to Test Step 8.
8. Check Machine Harness For A Short To Ground. A. The machine harness remains disconnected from the solenoid. B. Turn the key start switch and the disconnect switch OFF. C. Disconnect the harness connectors from the ECM. D. At the harness connector for ECM, measure the resistance between the solenoid signal contact and all ground contacts.	Each reading is greater than 5K Ω.	OK - Machine harness correct. Proceed to Test Step 9. NOT OK - One or more of the resistance measurements are less than 5 Ω. A short circuit exists in the machine harness. Repair: A short circuit exists between the wire for the signal wire of the solenoid and the circuit with the low resistance. 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. STOP
9. 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 safety lock lever. E. Check if diagnostic code for the solenoid is active.	Code for solenoid is NO longer present.	OK - The diagnostic code does not exist at this time. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. STOP NOT OK - 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, contact the Technical Communication 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
Begin Process For FMI 7 Troubleshooting HERE
10. Check The Pressure At The Park Brake Solenoid. A. Use Cat ET to monitor the park brake pressure circuit. B. Make sure the transmission is set to NEUTRAL and start the engine. C. Maintain pressure on the primary brake. D. Press the Park Brake switch to shut off the Park Brake.	The park brake is released within the 10 second interval. The system pressure has exceeded 1918 kPa (278 psi).	OK - The Park Brake is disengaged within 10 seconds of pressing the switch. Proceed to Test Step 11. NOT OK - The Park Brake solenoid does not disengage the park brake within the 10 second interval. The ECM did not detect a pressure greater than 2987 kPa ( 439 psi), to disengage the park brake. Repair - Most likely, the hydraulic system is blocked and not allowing the required pressure to pass to the park brake. A mechanical problem can also create faults within the park brake system. At ambient temperatures of −32° C (−25° F) or below, the viscosity of the oil can impact the hydraulic system, reducing the maximum pressure of the system. STOP
11. Check For Diagnostic Codes Related To Pressure Sensors. A. Check for diagnostic codes of pressure sensors that provide input to the ECM for controlling this specific solenoid.	The pressure sensors associated with specific solenoid are working properly.	OK - There are NO-related diagnostic codes associated with failures of the specified pressure sensors. Repair - If no failure is identified, replace the ECM. Prior to replacing an ECM contact the Technical Communicator at your dealership for possible consultation with AVSpare. If the Machine ECM must be replaced see Testing and Adjusting, " ECM - Replace". NOT OK - There are related diagnostic codes for failures of pressure sensors. Exit this procedure and perform the diagnostic procedures for the diagnostic codes that are listed. STOP
Begin Process For FMI 11 Troubleshooting HERE
12. Check The ECM. A. Turn the key start switch and the disconnect switch to the OFF position. B. Wait for 30 seconds. C. Turn the disconnect switch to the ON position. D. Turn the key start switch to the ON position. E. Allow the self test to run fully before you proceed to the next step. F. Check the message center for an active diagnostic trouble code. G. The diagnostic code being tested is no longer present.	The diagnostic code being tested is no longer present.	OK - The diagnostic code being tested is no longer present. Resetting the interface module has resolved the diagnostic trouble code. Resume normal machine operation. STOP NOT OK - The diagnostic code being tested remains active. The interface module has failed. Repair: Repeat the calibration procedure for the solenoid. Use the Cat^® Electronic Technician (Cat ET) service tool, to perform a "Wiggle Test" on the machine wiring harness. The wiggle test can detect momentary or intermittent shorts or opens in the machine wiring harness. If the cause of the diagnostic trouble code is not found, replace the ECM. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. See Troubleshooting, "ECM - Replace". Prior to releasing the machine confirm that the diagnostic code is no longer present. STOP
Begin Process For FMI 13 Troubleshooting HERE
13. Re-Calibrate The Solenoid. A. Re-Calibrate the solenoid. Follow the steps from the calibration program within Cat ET to complete the calibration.	A successful calibration causes this diagnostic code to become inactive.	OK - The calibration causes this diagnostic code to become inactive. Resume normal machine operation. STOP NOT OK - The calibration has not caused the diagnostic code to become inactive. Repair - Go to Troubleshooting, KENR6296, "Joystick Calibration Is Not Successful" to continue troubleshooting.