New Holland 4191 – ARU / CCU: Rear Remote No. 2 No Communications

The Armrest Control Unit (ARU) or Central Control Unit (CCU) has lost CAN bus communication with the electronic control unit integrated into the number 2 rear electro-hydraulic remote (EHR) valve. Expected messages from the second remote valve's controller are not being received, which may affect or disable the operation of the hydraulic functions controlled by this specific remote.

• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• T6.120
• T6.140
• T6.150
• T6.155
• T6.160
• T6.165
• T6.175
• T7.170
• T7.185
• T7.200
• T7.210
• T7.220
• T7.235
• T7.250
• T7.260
• T7.270
• T8030
• T8040

1. 1

   Visually inspect the wiring harness leading to the #2 rear remote valve stack for chafing, cuts, pinch points, or corrosion

2. 2

   Check electrical connectors at both the remote valve and the main controller for moisture, corrosion, and secure latching

3. 3

   Perform a CAN Bus Resistance Test (Power Off): Disconnect battery and measure resistance between CAN_H and CAN_L pins (expected: ~60 Ohms; ~120 Ohms indicates a missing terminating resistor or open circuit; significantly different readings indicate a wiring short or faulty module)

4. 4

   Perform a CAN Bus Voltage Test (Power On): Reconnect battery, turn ignition ON (engine off), and measure voltage to ground (expected: CAN_H ~2.5-3.5V, CAN_L ~1.5-2.5V; the sum should be around 5V, deviations indicate a short to power or ground)

5. 5

   Swap the electronic module/actuator from the #2 remote with an adjacent working remote (e.g., #3). If the fault code changes to 4192, the module is faulty; if 4191 remains, the issue is in the wiring or main controller

1. 1

   Repair Wiring and Connectors

   If the diagnostic checks reveal any damaged wiring or corroded connectors, repair or replace them first. Ensure all connections are clean and secure.

2. 2

   Isolate the Faulty Component

   Use the diagnostic checks, particularly component swapping, to determine if the fault lies with the valve's electronic module or the wiring harness.

3. 3

   Replace the Faulty Component

   If the electronic module on the valve is identified as the fault, replace it (often part of the complete remote valve slice). If the wiring harness is confirmed to be faulty, replace it.

4. 4

   Calibration and Configuration

   After replacing a remote valve module, perform a calibration or 'renumbering' procedure using the tractor's diagnostic display or Electronic Service Tool (EST) so the new module is recognized by the main controller.