Case IH 18251 - ACML – ACML: CVT Set Speed Encoder

Indicates an issue with the encoder dial/switch used by the operator to set the target ground speed for the Continuously Variable Transmission (CVT). The control module is detecting an open circuit, short circuit, or implausible signal from the encoder wheel.

• MAXXUM T4E
• VESTRUM CVX
• Case IH Maxxum
• Case IH Puma
• Case IH Magnum

1. 1

   Verify the connection between the CVT set speed encoder (usually a thumbwheel on the multicontroller joystick or armrest) and the ACML

2. 2

   Check for open or short circuits in the wiring harness connecting the encoder to the ACML

3. 3

   Check if other armrest-related codes (like 18255 or 18256) are present, which could indicate a broader failure of the ACML

1. 1

   Disconnect battery

   Disconnect battery power.

2. 2

   Disassemble housing

   Disassemble the multicontroller/armrest housing to access the encoder switch.

3. 3

   Inspect wiring

   Inspect the encoder wiring for chafing or pin damage.

4. 4

   Replace components

   Replace the faulty CVT Set Speed Encoder switch or the entire ACML if the internal circuit board has failed.

5. 5

   Recalibrate controls

   Recalibrate the armrest controls via the tractor's diagnostic display.