Case IH A-G-585 - Display – Navigation Controller (Nav Controller): Guidance GNSS Accuracy Limit

The GNSS receiver has dropped below the minimum accuracy threshold required for the active Autoguidance (A-G) operation. The system cannot maintain the required pass-to-pass accuracy due to satellite signal loss, convergence issues, or correction source degradation.

• MAGNUM AFS Connect
• STEIGER AFS Connect
• Magnum
• Steiger
• Maxxum
• Puma
• Optum
• Axial-Flow 5130
• Axial-Flow 7150
• Axial-Flow 7230
• Axial-Flow 7240
• Axial-Flow 8250
• Axial-Flow Mid Range Common Cab
• Patriot

1. 1

   Verify that the GNSS receiver has a clear line of sight to the sky. Check the correction signal status (RTX or RTK). If using RTX, ensure the subscription activation code is entered and active.

2. 2

   For RTX correction, verify the frequency is set to 1555.8080 MHz and the baud rate is 2400.

3. 3

   If using RTK, ensure the cellular data plan is active (if using a modem) and that the RTK Security or Modem Setup information is correctly entered.

4. 4

   Check the Autoguidance engage switch and harness connections to the UCM (User Control Module) for shorts or voltage irregularities.

1. 1

   Wait for Convergence

   Avoid turning, stop the vehicle, and press the 'Wait' button on the display to allow the GNSS receiver time to regain the required accuracy level.

2. 2

   Enable Position Recall

   Navigate to TOOLBOX > GPS and enable the 'Position Recall' feature to speed up signal convergence in the future.

3. 3

   Rerecord Swath Patterns

   If the accuracy limit was reached while recording a swath pattern, press the 'Cancel' button. The entire swath pattern must be recorded again once GNSS is fully available.

4. 4

   Perform Seasonal Calibrations

   If accuracy issues persist after the signal is restored, perform Autoguidance calibrations in a wide-open area. For Rear Wheel Position Calibration: Drive straight with guidance engaged, save the position, and measure the steering cylinder rod length (must be within 1/4 inch on both sides). Adjust if necessary. For Steering Valve Calibration: Ensure hydraulic oil is at operating temperature before calibrating.

5. 5

   Hardware Replacement

   If the receiver consistently fails to track satellites or maintain RTK/RTX correction despite proper configuration, active subscriptions, and clear skies, the GNSS receiver dome has likely failed internally and must be replaced.