Case IH 518592-02 - ACM – ACM: Transmission monitor shortcut switch circuit fault

The controller is detecting an erratic, intermittent, or incorrect data within the circuit (open circuit, short to ground, or short to power) on the transmission shortcut button.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series (Models 180, 200, 220, 240, 250, 280, 310, 340, 380, 400)
• Case IH Steiger AFS Connect Series

1. 1

   Inspect the specific switch on the armrest (transmission shortcut button) for physical damage, sticking, or debris like spilled liquids or dust.

2. 2

   Inspect the wiring harness connecting the armrest switch matrix to the main Armrest Control Module (ACM) for chafed wires, pinched harnesses under the armrest plastics, or loose connector pins.

3. 3

   Using a multimeter, back-probe the switch connector to verify the switch shows an open circuit when released and proper continuity (low resistance) when pressed.

4. 4

   Verify that the ACM is sending the correct reference voltage (usually 5V) to the switch circuit.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent shorting any sensitive CAN-bus components in the armrest.

2. 2

   Disassemble Armrest

   Carefully remove the plastic trim and retaining screws on the MultiControl Armrest to access the underside of the switch matrix.

3. 3

   Disconnect Switch Pod

   Locate the electrical connector for the affected switch pod (Transmission controls) and disconnect it from the ACM harness.

4. 4

   Test/Clean

   If the switch was sticking due to debris, clean the contacts with electronic contact cleaner. Test the switch again with a multimeter.

5. 5

   Replace Component

   If the switch fails the continuity test, replace the switch. Note: On AFS Connect armrests, individual buttons are often integrated into a larger sealed switch pod or keypad membrane. You may need to replace the specific pod assembly rather than a single plastic button.

6. 6

   Reassemble

   Reconnect the wiring harness, ensuring the connector clicks securely into place to prevent pin pushout. Reinstall the armrest trim.

7. 7

   Clear Codes

   Reconnect the battery, turn the ignition on, and use the AFS Pro 1200 display or a diagnostic tool to clear the inactive fault codes.

8. 8

   Verify

   Press the switch to ensure the transmission monitor opens and verify the fault code does not return.