Case IH 4356 – Tractor Control Unit (TCU) / Electronic Control Module (ECM): EHR FB 3 Shorted to low source / EHR FB 3 Low Err

The sensor feedback voltage drops below 0.25 V on the rear remote control / electro-hydraulic (EHR) system, specifically Remote No. 3. This suggests that the feedback signal is shorted to ground, experiencing an open circuit, or that the potentiometer itself has failed.

• Magnum
• Steiger T4B
• Maxxum
• Puma

1. 1

   Visually inspect the wiring harness running to the third remote valve for any rubbed, pinched, or broken wires that could cause a short to a low source.

2. 2

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

3. 3

   Ensure the connectors are fully seated, not damaged, the pins are in the correct position, and the fit is tight. Look for loose or corroded wiring.

4. 4

   Inspect the feedback/position sensor (potentiometer) on the third remote circuit for physical faults or damage.

1. 1

   Locate the Component

   Find the third remote valve (EHR valve #3) at the rear of the tractor.

2. 2

   Inspect and Repair Wiring

   Trace the wiring harness from the feedback sensor/potentiometer on remote #3 back to the TCU. Repair any rubbed, pinched, or broken wires.

3. 3

   Service Connectors

   Disconnect the implement interface (potentiometer) connector (C686) and the TCU connector (C063). Clean the pins and ensure a tight fit upon reconnection.

4. 4

   Replace the Sensor

   If the wiring and connectors are intact but the feedback voltage remains below 0.25 V, the potentiometer/sensor on the remote valve is defective. Remove the faulty sensor and install a replacement.

5. 5

   Replace ECM

   If the sensor and wiring are both verified as functional, the ECM itself may be faulty and require replacement.

6. 6

   Clear Codes

   Clear the error DTC code using an Electronic Service Tool or the tractor's diagnostic menu to reset the system and restore 3-point hitch/remote functionality.