Case IH 4267 – EHR / AUX Controller or Vehicle/Cab Controller: EHR master relay short to GND

A short to GND indicates that the electrical circuit controlling or powered by the EHR (Electronic Hydraulic Remote) master relay has found an unintended path to the machine's chassis ground. This happens when an exposed wire comes into contact with a grounded surface, or if a component fails internally. This condition typically causes excessive current draw, which will blow the circuit's protective fuse, disable the relay, and result in a complete loss of function for the electronic hydraulic remotes.

• MAXXUM T4E
• VESTRUM CVX
• Puma series (150, 185, 200, 220, 240)
• Magnum series
• Steiger / Quadtrac series
• Maxxum series

1. 1

   Check the cab fuse and relay box to see if the EHR system fuse has blown due to a short circuit

2. 2

   Remove and test the EHR master relay in the fuse panel to see if it has failed internally

3. 3

   Visually inspect the wiring harness running from the cab relay box to the EHR valve block at the rear of the tractor for chafed insulation, pinched wires, or exposed copper touching the metal chassis

4. 4

   Disconnect the EHR valve connectors and use a multimeter to check the resistance of the wiring (CAN BUS wiring between terminals 2 and 3 should read approximately 120 Ω)

5. 5

   Test the relay power and control circuits for continuity to ground to isolate where the short is located

1. 1

   Disconnect Power

   Turn off the battery disconnect switch to prevent electrical hazards while servicing the machine.

2. 2

   Isolate the Short

   Using the multimeter readings from your diagnostic checks, trace the specific wire that is shorting to the chassis.

3. 3

   Repair the Wiring

   If an exposed wire is found on the harness, repair the damaged section using appropriate electrical connectors and heat shrink, or replace that section of the harness.

4. 4

   Replace the Relay

   If the EHR master relay is not operating or is internally shorted, replace the relay with a new OEM unit.

5. 5

   Replace Fuses

   Install a new fuse of the correct amperage if the original was blown.

6. 6

   Test the System

   Reconnect the battery, power on the tractor, and use the Electronic Service Tool (EST) or the tractor's display to clear the fault codes. Test the EHR levers/switches to ensure the hydraulic remotes operate correctly.