Case IH 15339 – Precision Farming / Auto-Guidance System: IMD status signal cross-check failure (longer than specified by channel)

A CAN bus communication timeout or data mismatch indicating the guidance controller or display is expecting a continuous, synchronized status signal from the IMD, but the signal is either delayed, missing, or conflicting with other sensor data on that specific CAN channel.

• VESTRUM CVX
• STX Series Tractors (e.g., STX325)
• Magnum Tractors (e.g., Magnum 340)
• Flagship Axial-Flow Combines (e.g., 7088, 7230, 8230, 9230, 9120)
• SPX Sprayers (2009 or later)

1. 1

   Verify physical mounting of the IMD (must be rigid, neutral 0°, 0°, 0° orientation, dome facing up, connectors facing rearward, and away from loose objects)

2. 2

   Check CAN bus connections on the guidance controller and IMD (4-pin D code, 12-pin DTM, and CAN power cables) for security and corrosion

3. 3

   Check software calibration settings in the display (e.g., IMD-600 Orientation and roll calibration) for loss of calibration

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent voltage spikes on the CAN bus.

2. 2

   Inspect the Harness

   Trace the CAN cable from the IMD module to the NavController or Display. Look for pinch points, especially where the harness routes behind cab panels.

3. 3

   Test the CAN Network

   Use a multimeter to check the CAN terminator resistor (should read ~60 ohms across CAN High and CAN Low).

4. 4

   Reseat Connections

   Unplug and reconnect the IMD harness to wipe the pins clean of any micro-corrosion.

5. 5

   Recalibrate

   Power the system back on. Park the vehicle on a flat surface, mark the ground inside the wheels, and initiate the IMD roll/tilt calibration via the display. The system will take about 20 seconds to calculate compensation. Turn the vehicle around, park on the exact same marks, and complete the calibration.

6. 6

   Replace the IMD

   If the wiring is intact and calibration fails or the code immediately returns, the internal sensors of the IMD have likely failed and the module must be replaced.