New Holland NH 4175 – DU Module (Drive Unit Module): Rear EHR Control No.2 Short Circuit

The control module has detected a short circuit (either to ground or to another voltage source) in the electrical circuit that operates the #2 rear electro-hydraulic remote valve. When this occurs, the system typically switches the remote to a failsafe mode to prevent erratic hydraulic operation or electrical damage.

• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• TM115
• TM125
• TM135
• TM150
• TM165
• TM175
• TS100A
• TS115A
• TS125A
• TS135A
• T7 Series
• Maxxum
• Puma
• MXM series

1. 1

   Visual Wiring Inspection: Trace the wiring harness from the DU Module to the #2 rear EHR valve block. Look for chafed insulation, melted wires, or pinch points against the tractor chassis that could cause a short to ground.

2. 2

   Connector Inspection: Disconnect the harness at the #2 EHR valve. Inspect the pins for corrosion, moisture ingress, or bent pins that could be bridging the circuit.

3. 3

   Harness Continuity Test: With the battery disconnected and the DU module unplugged, use a digital multimeter to test the #2 EHR valve signal and ground wires for continuity to the chassis (ground) or to each other.

4. 4

   Solenoid Resistance Test: Measure the internal resistance of the #2 EHR valve solenoid itself. A reading of near zero ohms indicates an internal short within the solenoid coil, meaning the valve/solenoid assembly must be replaced.

1. 1

   Isolate Power

   Turn off the ignition key and disconnect the tractor's battery to prevent electrical spikes.

2. 2

   Access the Valve Block

   Locate the rear electro-hydraulic remote valve stack at the rear of the tractor and identify the #2 valve section.

3. 3

   Repair the Harness (If Applicable)

   If the diagnostic tests revealed a short in the wiring harness, repair the damaged section using weather-sealed splice connectors, or replace the affected harness section entirely.

4. 4

   Replace the Valve (If Applicable)

   If the short is internal to the valve solenoid, disconnect the hydraulic lines (relieve pressure first) and remove the retaining bolts for the #2 EHR valve section. Install the new valve/solenoid assembly and torque to OEM specifications.

5. 5

   Reassemble

   Reconnect the electrical harness to the valve and reconnect the battery.

6. 6

   System Calibration

   Enter the tractor's configuration menu and perform the HITCH Electronic Draft Control / EHR Calibration. This is required for the DU module to learn the parameters of the new valve and clear the failsafe lockout.

7. 7

   Clear Codes

   Clear the NH 4175 fault code from the DU module and test the #2 remote for proper operation.