John Deere SBU522387.07 – SSU: Wheel Angle Sensor Problem

The Steering System Control Unit (SSU) has failed to receive a valid signal from the wheel angle position sensor. This disruption in communication prevents the AutoTrac system from accurately determining the direction of the wheels, leading to the system disengaging.

• 5090R
• 5100R
• 5115R
• 5125R
• 7200R
• 7210R
• 7230R
• 7290R
• 7630
• 7730
• 7830
• 7930
• 8130
• 8225R
• 8230
• 8235R
• 8245R
• 8260R
• 8270R
• 8285R
• 8295R
• 8310R
• 8320R
• 8330
• 8335R
• 8345R
• 8360R
• 8430
• 8530
• 9230
• 9330
• 9430
• 9530
• 9630
• 4730
• R4030
• R4038
• R4044
• R4045
• R4060

1. 1

   Jack up the front of the tractor and attempt to move the tires to check for looseness or play in steering components (ball joints, tie rods) that could cause unintended sensor movement.

2. 2

   Inspect the wheel angle sensor's mounting to ensure it is secure and that the shaft it sits on is not too long, which could cause binding.

3. 3

   Examine the sensor's mechanical linkage for any signs of binding, rust, or stiffness.

4. 4

   Visually inspect the wiring harness leading to the wheel angle sensor for chafing, pinching, or corrosion, particularly the section running from the side of the engine to the sensor.

5. 5

   Wiggle the harness while monitoring the sensor readings on the display to check for an intermittent signal (indicating a wiring issue).

6. 6

   Disconnect and inspect the sensor connectors for corrosion, pushed-out pins, or a loose fit.

7. 7

   Perform a voltage drop test on the wires running from the SSU controller to the wheel angle sensor to ensure they can carry the required electrical load.

8. 8

   Check with a John Deere dealer for applicable Service Bulletins (PIPs) or DTAC solutions, such as PIP 08RW449 for the EH steering valve or DTAC solution 70749 for a software update.

1. 1

   Repair wiring or mechanical issues

   Based on the diagnostic checks, repair or replace any faulty wiring harnesses, connectors, or mechanical steering components before proceeding to sensor replacement. The wiring harness is a common failure point.

2. 2

   Replace the wheel angle sensor

   If the wiring and mechanical components are sound, replace the wheel angle sensor. It is typically located on the front axle, connected to the steering linkage.

3. 3

   Calibrate the new sensor

   After replacing the wheel angle sensor or any related steering components, initiate a calibration through the tractor's diagnostic menu on the display. Perform this on a firm, level, and dry surface, following the on-screen prompts to allow the SSU to learn the voltage ranges for full left and full right turns. If calibration fails, re-check all installation requirements.