John Deere 523961.02 – ACU / UIC / TIA: Park Lock Pressure Sensors Has Noted A Pressure Signal After Park Lock Disengage Signal Has Been received

Generated when the control software detects a park lock engagement signal from the park lock pressure sensor, even though the reverse drive lever is not in the park position. The control unit may automatically default the transmission to neutral to prevent the tractor from moving and causing mechanical damage. Note: This code can sometimes be generated by mistake during a transmission calibration procedure.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6230
• 6330
• 6430
• 7720
• 7820
• 7920
• 8130
• 8230
• 8330
• 8430
• 8530
• 7185J
• 7195J
• 7205J
• 7210J
• 7225J

1. 1

   Restart and Test: Restart the tractor and operate it slowly in forward gear. If the code was a temporary glitch, it may clear and not return.

2. 2

   Verify Park Lock Mechanism: Inspect the physical park lock mechanism to ensure it is functioning correctly and is not physically stuck or damaged.

3. 3

   Inspect Reverse Drive Lever: Check the reverse drive lever to ensure it moves freely into the correct positions and that the sensor for the park position is functioning properly.

4. 4

   Check Wiring and Connections: Ensure that all wiring and connectors related to the park lock system (specifically the pressure sensor and lever switch) are secure and free from damage, shorts, or corrosion.

5. 5

   Review Calibration: If the code was generated during transmission calibration, reset the calibration process and ensure it is performed correctly.

1. 1

   Clear and Retest

   Cycle the tractor's power. Shift the reverse drive lever to Park, start the engine, and shift into forward gear. If the code returns, proceed to hardware diagnostics.

2. 2

   Test the Reverse Drive Lever Sensor (Component S80 / A82)

   Use a multimeter or John Deere Service ADVISOR to verify the signal from the reverse drive lever. Ensure the signal matches the physical position of the lever and does not show "Park" when in gear.

3. 3

   Test the Park Lock Pressure Sensor (Component B90)

   Check the voltage at the park lock pressure sensor. Ensure it is receiving the correct 5V reference and that the signal wire is not shorted to ground or shorted to high voltage.

4. 4

   Inspect the Harness

   Trace the wiring harness from the B90 pressure sensor and the S80 reverse drive lever back to the ACU/UIC/TIA module. Look for rubbed wires, pinched harnesses, or corroded connector pins. Repair as necessary.

5. 5

   Inspect the Park Lock Solenoid (Component Y15/2)

   If the sensors and wiring are intact, test the park lock solenoid valve to ensure it is properly actuating and releasing hydraulic pressure to the park lock mechanism.

6. 6

   Replace Faulty Components

   Replace any sensors, switches, or solenoids that fail the electrical tests.

7. 7

   Recalibrate

   After replacing any transmission sensors or control modules, perform a full transmission and park lock calibration using John Deere Service ADVISOR.