Case IH 518673.09 - ACML – ACML: EHR lamps/controls data plausibility - Abnormal Update Rate

A CAN bus communication issue where the control module is not receiving the expected data messages from the EHR lamps/levers at the correct time interval (timeout or message lost), resulting in a data plausibility error.

• MAXXUM T4E
• VESTRUM CVX
• Magnum 180
• Magnum 200
• Magnum 220
• Magnum 235
• Magnum 240
• Magnum 250
• Magnum 260
• Magnum 280
• Magnum 290
• Magnum 310
• Magnum 340
• Magnum 380
• Puma 125
• Puma 140
• Puma 150
• Puma 165
• Puma 185
• Puma 200
• Puma 220
• Steiger 370
• Steiger 420
• Steiger 470
• Steiger 500
• Steiger 540
• Steiger 580
• Steiger 620
• Maxxum 115
• Maxxum 125
• Maxxum 135
• Maxxum 145
• Maxxum 150
• Farmall 110A
• Farmall 120A
• Farmall 130A
• Farmall 140A

1. 1

   Verify if the Electronic Service Tool (EST) can communicate with the Armrest Control Module (ACM). If multiple devices are failing to communicate, the issue is likely the main data link wiring, power, or ground circuits.

2. 2

   Check for an open circuit, short circuit, or physical disturbance on the CAN bus data link circuits connecting the EHR levers to the ACM.

3. 3

   Verify that proper electrical power and ground are being supplied to the ACM and the EHR panel.

4. 4

   Check the diagnostic data for the EHR lever positions (levers 1 through 6). Look for secondary fault codes indicating voltage is 'too high' or 'too low' at the EHR remote control valves, which would point to a specific failed lever potentiometer/encoder rather than the whole module.

1. 1

   Connect Diagnostic Tool

   Hook up the Case IH Electronic Service Tool to read all active and stored fault codes. Confirm if 518673.09 is isolated or accompanied by ACM communication loss codes (e.g., Trans 2818).

2. 2

   Inspect the Armrest Harness

   Remove the armrest console covers and inspect the wiring harnesses connecting the EHR levers and the EHR Flow Control Encoders to the ACM. Look for pinched wires, chafing, or loose connector pins.

3. 3

   Test CAN Bus Integrity

   With the batteries disconnected, measure the resistance across the CAN High and CAN Low pins at the armrest connector to ensure the data link is intact and terminating resistors are functioning (should typically read ~60 ohms).

4. 4

   Replace Faulty Components

   If the wiring is intact but the abnormal update rate persists from a specific EHR input, replace the faulty EHR lever, encoder, or the EHR panel assembly.

5. 5

   Module Replacement (If Necessary)

   If the EHR inputs are functioning but the ACM is failing to process or broadcast the CAN messages, the Armrest Control Module itself must be replaced.

6. 6

   Clear and Calibrate

   After replacing parts, clear the fault codes. If the ACM or EHR levers were replaced, perform the necessary spool and lever calibrations via the service tool or tractor display.