John Deere 523953.03 – ACU, AIC, or UIC: The Signal From The Vario Speed Lever Position Sensor Is Not In Range High Voltage

The control unit is measuring a voltage of more than 4.5 volts at the signal input from channel 1 of the speed control lever's potentiometer (B67, lead 6037). This high voltage condition typically indicates a problem with the signal lead wire, a failed potentiometer, or a bad ground connection at the potentiometer.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7720
• 7820
• 7920
• 7630
• 7730
• 7830
• 7930
• 8130
• 8230
• 8330
• 8430
• 8530
• 8310RT
• 8335RT
• 8360RT
• 7185J
• 7195J
• 7205J
• 7210J
• 7225J

1. 1

   Restart the tractor engine to perform a system reset and clear temporary communication glitches

2. 2

   Inspect wiring connections at the speed control lever potentiometer under the armrest for loose, corroded, or damaged pins

3. 3

   Check the harness routing behind the seat for physical damage, chafing, or rodent damage causing a short to power

4. 4

   Measure the voltage at the signal lead (lead 6037) to confirm it exceeds 4.5 volts

5. 5

   Inspect the ground connection to the potentiometer to ensure it is secure and free of corrosion (a lost ground causes the signal voltage to spike high)

1. 1

   Park the tractor on a level surface, turn off the engine, and disconnect the battery to prevent electrical shorts.

2. 2

   Disassemble the CommandARM / armrest control console to access the bottom of the IVT speed control lever.

3. 3

   Disconnect the electrical harness from the speed control lever potentiometer (B67).

4. 4

   If the diagnostic checks revealed a broken ground wire or a shorted signal wire in the harness, repair the damaged section of the wiring loom and re-pin the connector if necessary.

5. 5

   If the wiring and ground are perfectly intact but the voltage remains out of range, the potentiometer itself has failed internally. Remove the mounting screws holding the potentiometer to the speed control lever assembly and replace it with a new unit.

   On some models, the potentiometer cannot be purchased separately and the entire speed control lever assembly must be replaced.

6. 6

   Reassemble the armrest console, reconnect the battery, and start the tractor.

7. 7

   Acknowledge and clear the code on the CommandCenter display. Test the IVT lever in forward and reverse to ensure the tractor moves properly and the code does not return.