John Deere 523954.11 – ACU / UIC / AIC / DOI: Set Speed Adjuster Circuit Conflict / Sensor Unit for Speed Control Lever (Speed Wheel), Output Signals do Not Match

The control unit has detected an incorrect combination of voltage signals at the output channels (specifically channel 1, lead 6079 and channel 2, lead 6048) of the speed wheel on the sensor unit for the speed control lever (component S108). This discrepancy can be caused by electrical issues (wiring/sensor failure) or by operator actions, such as constantly changing the speed setting up or down by one count.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6230
• 6330
• 6430
• 7720
• 7820
• 7920
• 7185J
• 7195J
• 7205J
• 7210J
• 7225J
• 8130
• 8230
• 8330
• 8430
• 8530
• 8310RT
• 8335RT
• 8360RT
• 8245R
• 8400R

1. 1

   Verify operator habits — constantly clicking the speed setting up or down by one count can trigger this code without a hard hardware failure

2. 2

   Restart the machine — place the tractor in park, shut off the engine, and restart to verify if the active Service Code reappears, as resetting communication messages can sometimes clear the code

3. 3

   Inspect the set speed adjuster circuit and wiring connections at the speed wheel sensor unit (S108) for loose, damaged, or corroded connectors

4. 4

   Measure voltage output signals at channel 1 (lead 6079) and channel 2 (lead 6048) using a digital multimeter (John Deere tool JDG1478) to confirm the discrepancy and identify fluctuations

5. 5

   Check for any software updates that might address instability issues related to the speed adjuster circuit

1. 1

   Recalibrate

   Recalibrate the speed control settings according to the manufacturer's guidelines.

2. 2

   Repair Wiring

   If the multimeter test reveals intermittent faults in the wiring or connectors causing signal mismatches, repair or replace the affected harness sections.

3. 3

   Replace Sensor

   If the wiring and connections are intact but the signal discrepancy remains at the output channels, the sensor unit itself is faulty. Replace the Sensor Unit for the Speed Control Lever (S108).

4. 4

   Clear Codes

   After replacement, clear the codes and test the speed control lever through all speed bands to ensure the voltage conflict does not return.