New Holland 4172 – ARU / MIU / TCU / CCH: EHR Control Lever No.1 Short Circuit

The electronic control system has detected an electrical short circuit in the wiring or internal components of the number 1 Electro-Hydraulic Remote (EHR) control lever. The signal voltage from the lever is outside its expected range, indicating a short to ground or another wire. This fault indicates an electrical issue within the circuit associated with this component and will typically disable the function of the corresponding hydraulic remote valve.

• T7
• T8
• T9
• T6030
• T6050
• T6070
• T7030
• T7040
• MXM Series
• Optum
• Vestrum

1. 1

   Carefully inspect the wiring harness leading to and from the No. 1 EHR control lever for physical damage such as chafing, pinching, or melted insulation. Check for corrosion or moisture in the connectors.

2. 2

   Check for low battery voltage (ensure it is above 12.6V) and verify that all main power and ground connections to the chassis are clean and tight, as low voltage can trigger erroneous fault codes.

3. 3

   If the tractor has multiple identical EHR levers, swap the electrical connectors between the faulty lever (No. 1) and a known working lever (e.g., No. 2). If the fault code changes to indicate lever No. 2, the lever itself has failed. If the fault remains on lever No. 1, the issue is in the wiring harness or control module.

4. 4

   Disconnect the harness from the EHR lever and the control module. Using a multimeter, check for continuity to ground on the signal wire for lever No. 1 (there should be no continuity). Also check for shorts between the signal wire and other wires in the harness.

1. 1

   Park Safely

   Park the tractor on a level surface, engage the parking brake, and block the wheels.

2. 2

   Disconnect Power

   Turn the key to the 'OFF' position and disconnect the battery to prevent electrical damage during repair.

3. 3

   Access components

   Remove the necessary armrest covers or panels to gain access to the EHR control lever and its wiring.

4. 4

   Repair or replace wiring

   If diagnostic checks revealed a damaged wiring harness, repair the affected wires with appropriate connectors and heat shrink tubing, or replace the entire harness section if damage is severe.

5. 5

   Replace EHR control lever

   If the lever itself is determined to be faulty, disconnect its electrical connector, remove the mounting hardware, and replace it with a new part.

6. 6

   Reassemble and reconnect

   Reconnect all electrical connectors, reassemble the armrest panels, and reconnect the battery.

7. 7

   Perform EHR lever calibration

   Navigate to the H1 menu on the instrument cluster and select the rear EHR symbol ('CAL'). Press the program switch for lever No. 1 three times. Move the lever to neutral when '1' is displayed, full raise when '2' is displayed, full flow lower when '3' is displayed, and float when '4' is displayed. Turn the key to the 'OFF' position to store the new calibration values.

8. 8

   Clear fault codes

   Use the instrument cluster or the Electronic Service Tool to clear the stored fault codes and verify that the repair was successful.