Case IH 4355 – EHR (Electronic Hitch/Hydraulic Remote) / TCU (Tractor Control Unit): EHR FB 3 Shorted to high source

The tractor's control unit is detecting that the sensor feedback voltage on the third remote (valve) circuit is greater than 4.5 V. This indicates a short circuit to a high voltage source (B+ power) in the hydraulic feedback or position sensor circuit.

• Magnum
• Steiger T4B
• Magnum Series 235-340 (Series 4)
• Magnum 315
• Magnum 340
• STX Steiger Series
• Puma Series
• Maxxum Series
• Farmall Series
• NH 8670

1. 1

   Inspect the Tractor Control Unit (TCU) connector (C063 or C066) and the implement interface/potentiometer connector (C686)

2. 2

   Verify pin fitment to ensure connectors are fully seated, undamaged, pins are in the correct position, and the fit is tight

3. 3

   Test for a short to B+ power (high voltage source) using back probes at the implement interface (potentiometer) connector

4. 4

   Inspect the wiring harness between the TCU and the EHR valve 3 potentiometer for chafing, melting, or exposed wires causing the short

1. 1

   Repair Wiring/Connectors

   If the diagnostic checks reveal a damaged connector or a short in the wiring harness, repair or replace the affected section of the harness.

2. 2

   Software Update

   If the connectors and harness test okay (no physical short found), connect the Electronic Service Tool and download/flash the correct (latest) level of software to the control unit.

3. 3

   Replace the Sensor

   If the wiring is good, the software is up to date, and the fault code re-occurs, the internal circuitry of the sensor has failed. You must remove and replace the implement interface (potentiometer) on the EHR valve 3.

4. 4

   Clear Codes

   After the repair, clear the error codes and test the hydraulic system for normal operation.