Case IH NH4179 – EHR/AUX: EHR Control No.3 Short Circuit

The tractor's control module has detected an electrical short in the circuit for the third rear electro-hydraulic remote (EHR) valve. This indicates an abnormal electrical pathway, such as a wire grounding out or a failed electrical component, which will affect the proper operation of the No. 3 remote valve system.

• Maxxum Series
• Puma Series
• Quadtrac Series
• Magnum Series

1. 1

   Visually inspect the wiring harness leading to the No. 3 rear remote valve for chafing, cuts, or heat damage, paying close attention to areas routed near moving parts or articulation joints.

2. 2

   Disconnect the electrical connector at the No. 3 remote valve solenoid and inspect the pins and terminals for corrosion, moisture, or bent/dislocated pins. Clean the connectors and ensure a secure connection.

3. 3

   Perform a solenoid resistance test by measuring across the two pins of each solenoid (raise and lower) at the No. 3 remote valve. Normal reading is between 4 and 8 ohms.

4. 4

   Perform a wiring harness continuity and short-to-ground test on each wire between the controller connector and the valve connector.

5. 5

   Perform a short-to-power test to ensure no voltage is present on the signal wires when the control lever is in the neutral position.

1. 1

   Isolate the fault

   Based on the diagnostic checks, determine if the fault lies with the solenoid, the wiring harness, or the controller.

2. 2

   Replace remote valve solenoid

   If the solenoid resistance test yields less than 3 ohms (indicating a short circuit within the coil) or higher than 10 ohms (indicating an open circuit), replace the solenoid on the remote valve.

3. 3

   Repair or replace wiring harness

   If a short circuit or break is found during continuity testing, repair the damaged section of wire and seal it properly to prevent moisture intrusion. If the damage is extensive, replace the entire EHR control valve wire harness.

4. 4

   Replace EHR/AUX controller

   If both the solenoids and the wiring harness test correctly, but the controller outputs voltage to the solenoid circuit when the lever is in neutral, the fault likely lies within the EHR/AUX controller. Replace the controller after re-verifying all other components.

5. 5

   Clear fault codes

   After completing the repair, clear the fault codes from the system using a diagnostic tool or through the tractor's onboard diagnostic menu.

6. 6

   Calibrate and test

   Recalibrate the EHR remote valves if necessary. Operate the No. 3 remote valve to ensure it is functioning correctly and that the fault code does not reappear.