New Holland NH 4178 – DU Module: EHR Control No.3 open circuit

The control module has detected a break in the electrical circuit (an open circuit) that controls the #3 rear hydraulic remote valve. This is typically caused by a disconnected plug, a broken wire in the harness, or a failed (open) solenoid coil inside the valve itself.

• T6
• T7
• T7030
• T7040
• T7050
• T7060
• T8
• T8.275
• T8.390
• T9
• T6000 Series
• TM 175
• MXM/TM
• SWB PUMA

1. 1

   Visually inspect the rear remote valve block (#3 valve slice) and wiring harness for physical damage, chafing, or breaks.

2. 2

   Disconnect the electrical plug at the #3 EHR valve and check for pushed-out pins, heavy corrosion, water ingress, or loose connections.

3. 3

   Measure the resistance across the pins of the #3 EHR valve solenoid using a multimeter (a healthy 12V solenoid reads 7.3-9.9 Ohms; an OL reading indicates an open coil).

4. 4

   Perform a continuity test on the wiring harness from the valve connector back to the EHR control module to isolate any broken wires if the valve coil tests good.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent short circuits.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken wire or a faulty connector, splice in a new connector pigtail or repair the damaged wire section using weather-sealed heat shrink connectors.

3. 3

   Replace Solenoid/Valve

   If the solenoid coil tested open, remove the retaining hardware on the #3 EHR valve slice and replace the solenoid coil (or the entire valve slice, depending on whether your specific valve block allows the solenoid to be serviced separately).

4. 4

   Reassemble

   Reconnect the electrical harness to the valve. Ensure the connector clicks into place and is secure.

5. 5

   Clear Codes & Calibrate

   Reconnect the battery and turn the key on. Clear the inactive fault codes.

6. 6

   EHR Calibration

   Access the tractor's display monitor, navigate to the Electro-hydraulic control valve configuration menu, and initiate the calibration process for Valve #3. Note: If calibration fails the first time, stroke the valve back and forth manually to clear any debris, then retry.