Case IH 15219 - AST – AST: Primary wheel angle sensor (AD1) – signal crosscheck failed

The voltage signal from the primary wheel angle sensor does not match the expected value of the redundant sensor or the controller's internal calculations, forcing the system to disable auto-steering.

• MAXXUM T4E
• VESTRUM CVX
• Puma
• Maxxum
• Optum
• Magnum
• Steiger
• Farmall

1. 1

   Visually inspect the Wheel Angle Sensor (WAS) on the front steering axle for physical damage, a bent linkage arm, or loose mounting brackets.

2. 2

   Inspect the wiring harness and connector to the AST controller for pinched wires, corrosion, or moisture ingress.

3. 3

   Monitor live voltage output of the primary wheel angle sensor using the on-board diagnostic display (H Menu) or an Electronic Service Tool while slowly turning the steering wheel lock-to-lock, watching for erratic spikes or dead spots.

4. 4

   Attempt a Wheel Angle Sensor Calibration, as the controller may have lost its calibration parameters.

1. 1

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

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

2. 2

   Locate the primary wheel angle sensor on the steering axle.

   Locate the primary wheel angle sensor on the steering axle.

3. 3

   Disconnect the electrical harness connector from the sensor.

   Disconnect the electrical harness connector from the sensor.

4. 4

   Remove the retaining ring/hardware and detach the sensor linkage arm from the axle.

   Remove the retaining ring/hardware and detach the sensor linkage arm from the axle.

5. 5

   Unbolt the sensor body from its mounting bracket and remove the faulty unit.

   Unbolt the sensor body from its mounting bracket and remove the faulty unit.

6. 6

   Install the new wheel angle sensor into the bracket and secure the mounting bolts.

   Install the new wheel angle sensor into the bracket and secure the mounting bolts.

7. 7

   Reattach the linkage arm and secure it with the retaining hardware.

   Reattach the linkage arm and secure it with the retaining hardware.

8. 8

   Reconnect the electrical harness, ensuring the weather seal is intact.

   Reconnect the electrical harness, ensuring the weather seal is intact.

9. 9

   Reconnect the battery and power on the tractor.

   Reconnect the battery and power on the tractor.

10. 10

    Perform a Wheel Angle Sensor Calibration (WAS Auto-Calibration) using the tractor's diagnostic H Menu or an EST.

    Mandatory Calibration: You must perform a Wheel Angle Sensor Calibration (WAS Auto-Calibration) using the tractor's diagnostic H Menu or an EST. The AST controller must learn the new sensor's specific millivolt outputs for the leftmost, rightmost, and center steering positions.

11. 11

    Clear the 15219 fault code from the AST module and test drive the tractor to verify auto-steer functionality.

    Clear the 15219 fault code from the AST module and test drive the tractor to verify auto-steer functionality.