Case IH F-GNSS-101 - Display – Guidance and GNSS System: Display: "GNSS Position Lost"

A "Medium" severity issue where the GNSS receiver is unable to determine its two-dimensional coordinate position, or the position accuracy has dropped to a very low level. The receiver is not tracking enough satellites to compute a position (requiring at least 3 satellites in view) or has lost its correction signal.

• MAGNUM AFS Connect
• STEIGER AFS Connect
• Magnum
• Optum
• Puma
• Steiger
• Axial-Flow
• Patriot
• Trident
• Farmall
• Vestrum
• Maxxum

1. 1

   Move the vehicle to a flat, open area with a clear view of the sky, away from buildings, trees, or other obstructions. Allow 2–10 minutes for the receiver to re-establish a position lock.

2. 2

   Access the 'GPS Setup' or 'GPS Receiver' screen on the AFS display (Home > Toolbox > GPS) to verify that at least 3 satellites are in view.

3. 3

   On receivers like the AG-372, check the LED status. A fast-flashing yellow LED indicates not enough GNSS signals to compute position.

4. 4

   Ensure the receiver is receiving 12 VDC power. Check the DB9 serial cable or CAN bus harness connections between the receiver and the display for damage or loose pins.

5. 5

   If using RTK or RTX, verify on the AgRemote screen that CMR corrections are being received and that your subscription/activation code is still valid.

1. 1

   Harness/Cable Replacement

   If diagnostic checks reveal a damaged antenna cable or receiver harness, disconnect the battery, replace the damaged cable (e.g., TNC/TNC antenna cable or main power/data harness), and route it safely away from pinch points.

2. 2

   Receiver Replacement

   Disconnect the power/data harness from the faulty GNSS receiver. Unbolt the receiver from the mounting plate assembly (typically three bolts). Secure the new receiver to the mounting plate and torque the bolts to 75–80 inch-pounds.

3. 3

   Configuration

   Connect the receiver to a computer using a power data cable and use the Ag Remote utility to configure the device. Ensure that the CAN A Config and CAN B config are set properly, and make sure Self Config Addr is set to "Yes".

4. 4

   Clear BB Ram

   After a repair or replacement, clear the BB Ram to restore factory defaults before returning the machine to operation.

5. 5

   System Calibration

   Drive the machine straight forward for 50–100 meters at normal field speed, turn 180 degrees, and return along the exact same path to allow the system to record position offsets and recalibrate steering response.