Case IH 639-09 - IMM – IMM: J1939 Data Link communications failure

The control unit is experiencing a CAN bus timeout because it is not receiving the expected network messages within the required timeframe (2 seconds) after the key is turned on.

• MAGNUM AFS Connect
• Magnum 215
• Magnum 235
• Magnum 245
• Magnum 250
• Magnum 275
• Magnum 280
• Magnum 305
• Magnum 310
• Magnum 340
• Puma 125
• Puma CVX
• Combines/Harvesters

1. 1

   Check battery voltage during cranking to ensure it does not drop to 9-10 volts and stay below the threshold for too long.

2. 2

   Check for an open circuit or a short circuit in the J1939 data link wiring.

3. 3

   Verify if the Electronic Service Tool (EST) can communicate with the ECM to rule out a hard physical fault on the CAN bus.

4. 4

   Check for accompanying Diagnostic Trouble Codes (DTCs) to identify exactly which message or specific module is lost.

1. 1

   Test the battery

   Test the battery's health and its voltage drop during cranking. If it fails to recover voltage quickly, charge or replace the battery.

2. 2

   Inspect wiring and connectors

   Visually inspect the J1939 CAN bus wiring harness and connectors for damage, corrosion, or backed-out pins.

3. 3

   Perform circuit tests

   Use a multimeter to test the CAN data link circuits for continuity (to rule out an open circuit) and check for shorts to ground or power.

4. 4

   Repair the harness

   If physical damage is found in the wiring, splice and repair the affected CAN lines using approved CAN bus wiring repair connectors.

5. 5

   Clear codes

   Enter the machine's maintenance mode via the keypad or use the electronic service tool to select the 'LOGGED EVENT' option and clear the fault history.

6. 6

   Verify repair

   Cycle the key to ensure the CAN traffic resumes normally and the 639-09 code does not return.