Case IH 518924-19 - VCM – VCM: ISOBUS communication fault

Loss of communication or a data error on the ISOBUS network (CAN bus). The "-19" failure mode typically indicates "Received Network Data In Error" or a general communication timeout on the ISOBUS line, meaning the module is failing to send or receive expected messages to/from the implement or other tractor modules.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect
• Case IH Steiger AFS Connect
• Case IH Patriot Sprayers
• Case IH Puma Series
• Case IH Maxxum Series

1. 1

   Inspect the ISOBUS breakaway connector at the rear of the tractor and the implement connection for bent pins, corrosion, dirt, or moisture.

2. 2

   Inspect the wiring harness between the VCM/UCM and the ISOBUS diagnostic connector (CAN1/ISOBUS) for chafing, pinches, or breaks.

3. 3

   Verify battery voltage and ground connections to the VCM. Low voltage can cause communication drops.

4. 4

   Connect the Case IH Electronic Service Tool (EST) to the diagnostic connector (CAN1/ISOBUS). Check the CAN bus traffic to verify if the VCM is communicating with the PCM (Powertrain Control Module) or DEC (Drivetrain Electronic Controller).

5. 5

   If working on a sprayer (like the Patriot series with AIM Command/PinPoint systems), verify VCM compatibility (e.g., ensuring it is an A14 Style VCM without a 4-pin Weather Pac programming connector, rather than the incompatible A9 style).

1. 1

   Power Down

   Turn the ignition key OFF. Wait 2 to 5 minutes before disconnecting the batteries to allow the VCM/UCM to save data and power down correctly.

2. 2

   Clean and Reconnect

   Disconnect the ISOBUS harness at the VCM and the rear implement connector. Clean the contacts with electrical contact cleaner, apply dielectric grease, and securely reconnect them.

3. 3

   Harness Replacement

   If the diagnostic checks revealed a short or break in the CAN lines, replace the affected ISOBUS communication harness.

4. 4

   Module Replacement

   If the harness is intact but the VCM fails to communicate on the EST, the VCM/UCM must be replaced. Remove the module cover, disconnect the multi-pin OEM connectors, and unbolt the module from its mounting bracket.

5. 5

   Reconfiguration

   After installing a new VCM/UCM, reconnect the battery. Connect the EST to the diagnostic connector. Navigate to the toolbar, select "General Configuration," and configure the ISOBUS settings, machine PIN, and module logic to match the tractor's options.