Case IH 520618-02 - ACM – ACM: Transmission sensitivity switch circuit fault

Indicates an electrical issue, such as an open circuit, a short circuit to ground, or a short circuit to power within the switch's wiring harness or the switch itself.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect Series
• Case IH Steiger Series
• Case IH Puma Series
• Case IH Farmall V/N/F/CL Series

1. 1

   Use the electronic service tool or the display on the control panel to verify if the code is currently active or stored.

2. 2

   Disconnect the suspect switch connector and check for an open circuit or a short circuit in the harness.

3. 3

   Create a short circuit between the signal and the common terminals at the sensor/switch harness connector, then turn the keyswitch to the ON position to see if the diagnostic code changes (e.g., from an open circuit code to a short circuit code) to verify wiring integrity.

4. 4

   Verify the 17-pin connector assignments on the Armrest Control Module to ensure no pins are pushed back, corroded, or suffering from a loss of communication.

1. 1

   Replace the switch

   If the wiring harness tests good (no opens or shorts between the switch and the ACM), replace the faulty transmission sensitivity / constant engine speed switch on the armrest.

2. 2

   Replace or update the ACM

   If the switch tests good but the circuit fault persists, the Armrest Control Module itself may require replacement or a software update.