Case IH 522845-06 - PCM – PCM: Cellular diversity antenna short circuit to ground

The control module has detected that the voltage on the cellular diversity (4G) antenna circuit has dropped to zero, indicating that the signal wire is shorted to the chassis ground.

• MAGNUM AFS Connect
• Magnum AFS Connect tractors
• Steiger AFS Connect tractors
• Optum series tractors
• Puma series tractors
• Patriot 50 Series sprayers
• Axial-Flow combines

1. 1

   Identify the correct connector: The dual-mode antenna connects to the front of the PCM using three color-coded connectors. The Carmin Red (1A) connector is specifically for the Cellular - Diversity (4G) circuit.

2. 2

   Disconnect the Carmin Red (1A) connector from the PCM and inspect the pins for damage, moisture, or corrosion.

3. 3

   Using a multimeter, check for continuity between the center pin of the disconnected antenna cable and the machine's chassis ground. If continuity exists, the cable or the antenna itself is shorted internally.

4. 4

   Trace the antenna cable from the PCM up to the cab roof. Look for pinched wires, chafing against metal cab frames, or cuts in the insulation that would cause the wire to ground out.

1. 1

   Power down machine

   Power down the machine and turn off the main battery disconnect switch.

2. 2

   Disconnect antenna connectors

   Disconnect all three antenna connectors (Carmin Red, Blue, Bordeaux) from the front of the PCM.

3. 3

   Remove faulty antenna

   Remove the faulty dual-mode antenna from the cab roof and carefully pull the wiring harness out of the cab routing.

4. 4

   Clean mounting surface

   Clean the roof mounting surface.

5. 5

   Mount new antenna

   Mount the new dual-mode antenna using the provided adhesive pads. It must be placed on a flat mounting surface at the highest possible point of the vehicle cab. Mount the antenna a minimum of 20 cm (8 in) away from any other radio antennas (AM/FM, CB) and at least 20 cm (8 in) away from the PCM itself to avoid interference.

6. 6

   Route new antenna cable

   Route the new antenna cable with the cable exiting toward the rear of the cab roof, feeding it back down to the PCM.

7. 7

   Reconnect connectors

   Reconnect the three connectors to the PCM matching the color codes: Carmin Red (1A) to Cellular Diversity, Blue (2A) to GNSS, and Bordeaux (3A) to Cellular Main.

8. 8

   Verify repair

   Power on the machine, clear the fault code via the AFS Pro 700 / Pro 1200 display, and verify cellular network connectivity.