Case IH 18266 (518755.03, 518755.04) - ACML – ACML: Rear Hitch Draft Control Potentiometer circuit error state

The system is detecting that the voltage signal from the Rear Hitch Draft Control Potentiometer is either out of range high (.03) or out of range low (.04). When the signal falls outside the expected parameters, the system disables automated implement depth control and logs the fault.

• MAXXUM T4E
• VESTRUM CVX
• Magnum 7110
• Magnum 7120
• Magnum 7130
• Magnum 7140
• Magnum 7150
• Magnum 7210
• Magnum 7220
• Magnum 235
• Magnum 275
• Magnum 340
• Puma 165
• Puma 180
• Puma 195
• Puma 210
• Puma 220
• Puma 225
• Maxxum 135 Multicontroller
• MX80C
• MX90C
• MX100
• MX110
• MX120
• MX135
• MX150
• MX170
• MX210
• MX230
• MX255
• MX285
• CX50
• CX60
• CX70
• CX80
• CX90
• CX100
• Steiger 370

1. 1

   Visual Inspection: Inspect the wiring harness running from the ACML to the draft control potentiometer for chafing, breaks, or pinched wires.

2. 2

   Connector Check: Disconnect the potentiometer and inspect the pins for corrosion, moisture, or bent terminals.

3. 3

   Voltage Test: Using a multimeter, verify that the sensor is receiving a steady 5V reference signal and has a solid ground from the ACML.

4. 4

   Sweep Test: Measure the signal return voltage while manually moving the draft control linkage or dial. The voltage should sweep smoothly without dropping out or spiking (which would trigger the .03 or .04 voltage errors).

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery cable to prevent electrical shorts and reset the ACML.

2. 2

   Locate the Sensor

   Locate the faulty draft control potentiometer. Depending on whether the fault is tracing to the command dial or the linkage feedback sensor, it will be located either inside the armrest console or on the rear hitch lift linkage assembly.

3. 3

   Removal

   Disconnect the electrical harness connector from the potentiometer. Remove the retaining screws or mounting bracket holding the sensor in place.

4. 4

   Installation

   Install the new potentiometer, ensuring the mechanical linkage or dial aligns correctly with the sensor's internal tracking mechanism. Secure the mounting hardware.

5. 5

   Reconnect

   Plug the electrical harness back into the sensor and reconnect the battery.

6. 6

   Calibration

   Power on the tractor. You must perform a rear hitch calibration procedure via the tractor's display monitor so the ACML can learn the minimum and maximum voltage limits of the new potentiometer.