This procedure is used when the apron will not enter the float mode. This procedure is also used when the apron abruptly exits the float mode, and there are no active diagnostic codes.
Test Step 1. CHECK THE STATUS OF THE APRON FLOAT LAMP.
- Check the status of the apron float lamp.
Expected Result:
The apron float lamp never illuminates.
Results:
- YES - The apron float lamp never illuminates. Proceed to Test Step 2.
- NO - The apron float lamp illuminates. Proceed to Test Step 3.
Test Step 2. CHECK THE MOVEMENT OF THE THUMB ROLLER ON THE JOYSTICK (APRON CONTROL).
- The movement of the thumb roller must be unrestricted. If dirt gets in between the stationary portion of the joystick handle and the thumb roller, movement of the roller may be slow. Check the movement of the thumb roller.
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| Illustration 1 | g02570857 |
Thumb Roller | |
Expected Result:
The movement of the thumb roller is unrestricted.
Results:
- YES - The movement of the thumb roller is unrestricted.
Repair: Recalibrate the joystick. See Testing and Adjusting, "Implement Control Lever (Joystick) - Calibrate".
STOP
- NO - The movement of the thumb roller is restricted or the movement of the thumb roller is slow.
Repair: Clean the dirty portions of the joystick and the thumb roller to restore free movement to the thumb roller. Resume normal machine operation and check for proper operation of the controls.
STOP
Test Step 3. CHECK THE CURRENT AT THE APRON LOWER SOLENOID.
Note: CAT ET can be used in order to measure current at the solenoids. This procedure describes the use of the multimeter and AC current probe.
- Stop the machine and turn the key start switch to the OFF position.
- At the apron lower solenoid, connect the 349-4199 AC/DC Current Probe around wire R720-GY. Connect the leads from the current probe to the multimeter.
- Turn the key start switch to the ON position. Do not start the engine.
- Move the joystick into position in order to illuminate the apron float lamp.
- Measure the current to the apron lower solenoid.
Expected Result:
The current at the apron lower solenoid is above 1.3 A.
Results:
- YES - The current at the apron lower solenoid is above 1.3 A. It is likely that there is a hydraulic problem.
Repair: Diagnose the hydraulic problem and correct the problem. Refer to Testing and Adjusting, KENR8874, " 621H, 623H, and 627H Hydraulic and Steering Systems", "Troubleshooting"
STOP
- NO - The current at the apron lower solenoid is below 1.3 A. Proceed to Test Step 4.
Test Step 4. CHECK THE RESISTANCE OF THE APRON LOWER SOLENOID.
- Disconnect the machine harness connector from the solenoid.
- At the solenoid, measure the resistance from contact 1 to contact 2.
Expected Result:
The resistance is approximately 5 ohms.
Results:
- OK - The resistance is approximately 5 ohms. Proceed to Test Step 5.
- NOT OK - The resistance is not approximately 5 ohms.
Repair: Replace the solenoid.
STOP
Test Step 5. CHECK THE WIRING HARNESS.
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the machine harness connector J1 from the ECM.
- At the apron lower solenoid, disconnect the machine harness connector from the solenoid. Connect a jumper wire across the two terminals of the wiring harness connector.
- At the Implement ECM, measure the resistance from contact J1-58 (wire R717-BR) to contact J1-59 (wire R720-GY).
Expected Result:
The resistance measurement is less than 5 ohms.
Results:
- YES - The resistance is less than 5 ohms. The wiring is correct.
Repair: The ECM may have failed. It is unlikely that the ECM has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the Implement ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The resistance measurement is greater than 5 ohms.
Repair: The wiring harness has failed between the ECM and the apron lower solenoid. Repair the wiring harness or replace the wiring harness.
STOP