John Deere 520589.02 – PTQ: Transmission Speed Sensor Miss Match / Wheel Speed Sensor (Channel 2), Incorrect Speed

The control software expects a wheel/transmission speed signal from channel 2 but does not receive it, or there is a speed discrepancy of more than 10 km/h (6.2 mph) when compared to the wheel speed sensor on channel 1. When this error is detected, the control software will typically limit gear selection or disable transmission functions to prevent damage.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6R Series
• 7R Series
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 9470RT
• 9520RT
• 9570RT

1. 1

   Visually inspect the wheel/transmission speed sensor on channel 2 for any signs of physical damage, disconnection, or improper mounting/alignment.

2. 2

   Use a diagnostic tool to monitor live data from both wheel speed sensors (Channel 1 and Channel 2). Look for drop-outs, erratic readings, or a discrepancy of more than 10 km/h.

3. 3

   Inspect the wiring harnesses and connectors leading to the speed sensors for signs of wear, chafing, grounding, or corrosion.

4. 4

   Verify the PTQ control unit is correctly receiving the signals to rule out a software glitch causing false mismatches.

1. 1

   Power Down

   Turn off the tractor, place the shift lever in Park, and cycle the power to see if the code clears (sometimes required to reset the transmission enable status).

2. 2

   Repair Wiring

   If the diagnostic checks revealed damaged wires or corroded pins at the sensor connector, repair or replace the affected pigtail/connector.

3. 3

   Replace Sensor

   If the wiring is intact but the channel 2 sensor is dead or providing erratic readings, remove the retaining bolt, pull out the faulty speed sensor, and install a new OEM sensor. Ensure it is properly seated and aligned.

4. 4

   Software Update

   If the sensor and wiring are perfectly functional, reprogram or update the PTQ control unit software via Service ADVISOR.

5. 5

   Test and Monitor

   After repairs, test drive the tractor and monitor the wheel speed sensors to ensure they are providing accurate and consistent readings and that full transmission functionality has returned.