Case IH 18402 – Armrest Control Unit (ARU) / LC Controller / Instrument Control Panel (ICP): EHR 3 Program / Motor Mode Switch Error

The system has detected an invalid, missing, or erroneous CAN signal from the ICP regarding the position or state of the EHR 3 mode switch.

• VESTRUM CVX
• Case IH Puma Series (165, 180, 195, 210, 225 CVX)
• Case IH Magnum Series

1. 1

   Install the diagnostic connector (tool 380000843) into the diagnostic socket and turn the ignition key switch ON.

2. 2

   Use the 'h', 'm', and 'dimming' (or 'menu') buttons on the instrument cluster to navigate the 'HH' menus to the H5 menu (Switch operation test) on the LC controller.

3. 3

   Select the H5 menu by depressing the 'dimming' or 'menu' button. The lower central display will show 'd _ _'.

4. 4

   Manually operate the EHR 3 program / motor mode switch.

5. 5

   If the switch and CAN communication are working correctly, the code d97 will be displayed on the screen, and an audible tone will be heard.

6. 6

   If the d97 switch code is not displayed and the audible tone is not heard, perform a 'wiggle' test on the related wiring harness in the armrest while watching the display or listening for the tone. This will help locate an intermittent open or short circuit in the wiring.

1. 1

   Harness Inspection

   Based on the results of the H5 diagnostic test, inspect the wiring harness connecting the EHR 3 switch to the Armrest Control Unit (ARU) / ICP. Look for chafed wires, pinched harnesses under the armrest plastics, or backed-out pins at the connectors.

2. 2

   Connector Cleaning

   Disconnect the switch and the main ARU harness. Inspect for corrosion or moisture. Clean the contacts with electrical contact cleaner and apply dielectric grease.

3. 3

   Component Replacement

   If the wiring is intact but the H5 test still fails to register the d97 input, the physical EHR 3 switch has failed internally or the Armrest Control Unit's internal circuit board has a fault. Replace the switch (or the armrest module if the switch is non-serviceable on your specific trim).

4. 4

   Clear Codes

   After the repair, navigate to the error clearing menu (typically by holding down the 'm'/'Decr' key until the display scrolls through the EE memory and beeps) to clear the logged 18402 fault code.