Case IH 2802-12 - ACM – ACM (Armrest Control Module): Armrest controller internal failure

The module has suffered an internal fault where power supply or signal sensing has failed, specifically pointing to an internal CPU or EEPROM memory write error.

• MAGNUM AFS Connect
• Magnum Series 180
• Magnum Series 200
• Magnum Series 220
• Magnum Series 240
• Magnum Series 250
• Magnum Series 280
• Magnum Series 290
• Magnum Series 310
• Magnum Series 340
• Magnum Series 380
• Puma Series 140
• Puma Series 175
• Puma Series 200
• Steiger / Quadtrac Series 325
• Steiger / Quadtrac Series 430
• Steiger / Quadtrac Series 435
• Steiger / Quadtrac Series 470
• Steiger / Quadtrac Series 525
• Maxxum Series 16/17X16 Efficient Power

1. 1

   Connect the electronic service tool and use the MONITOR window to observe the switch states (e.g., transmission shift switches or remote hydraulic switches) to verify if the controller is receiving conflicting signals.

2. 2

   Visually inspect the external wiring harness for damaged wires, loose connectors, or bent pins.

3. 3

   Turn the tractor key switch to the ACC position and check the reference power supply coming from the armrest controller (e.g., at pin 1 of connector J2). It should read approximately 8 volts.

4. 4

   Measure the resistance of the connected potentiometers. Resistance should change smoothly (e.g., from 0.1 k to about 1.1 k ohms) without dropouts.

1. 1

   Access the Module

   Open the armrest controller housing.

2. 2

   Disconnect Connectors

   Disconnect the main connectors (such as J211 for transmission switches, SW205 for auxiliary remotes, or J205 for hitch controls) to isolate the ACM from the peripheral switches.

3. 3

   Test Isolated Wiring

   With the connectors unplugged, manually test the continuity of the switches (e.g., shifting up should show continuity between pins 1 and 2, but not 1 and 3).

4. 4

   Clean and Reconnect

   If the wiring and switches test good, clean the connector pins with contact cleaner and securely reconnect them to the ACM.

5. 5

   Calibrate

   Enter the tractor's Instrument Cluster (ICU2) programming mode or use the service tool to perform an Armrest Controller Calibration.

6. 6

   Verify

   Check the fault codes again. If code 2802-12 returns after calibration and wiring verification, the internal power supply/sensing circuit of the ACM is permanently damaged.

7. 7

   Replace

   Remove the faulty ACM and install the replacement module. Flash the correct software version for your specific tractor configuration and recalibrate the armrest.