New Holland 4121 – EHR: Rear Remote No. 2 Spool Movement Too High

The control system has detected that the movement of the Rear Remote No. 2 Spool is exceeding the expected range. The system commands a specific amount of spool travel, which is monitored by a position sensor (potentiometer). This fault triggers when the sensor feedback indicates the spool has moved beyond its expected range for a given command, potentially leading to erratic behavior or complete deactivation of the affected remote valve.

• T6 Series
• T6010
• T6090
• T6.120
• T6.180
• T7 Series
• T7.170
• T7.270
• T8 Series

1. 1

   Visual inspection: Carefully inspect the No. 2 rear remote valve block and its wiring harness for damage, corrosion on connectors, or loose wires. Ensure connectors are securely seated.

2. 2

   Check for related fault codes: Scan for codes like 4125 (Position Transducer Faulty) which strongly indicates a sensor issue, or 4123 (Manually Operated).

3. 3

   Check system voltage: Ensure the battery is fully charged and that all main power and ground connections to the cab and controllers are clean and tight, as electronics can be sensitive to low voltage.

4. 4

   Potentiometer/Position sensor test: Disconnect the sensor and check for a stable 5-volt reference supply and good ground. Back-probe the signal wire to ensure voltage changes smoothly as the spool is commanded to move. Measure resistance across terminals for a smooth sweep without open spots or spikes.

5. 5

   Manual operation check: Check for any debris or mechanical obstruction that could be forcing the spool to move externally.

1. 1

   Isolate faulty component

   Based on diagnostic checks and related codes (like 4125), determine if the fault lies with the position sensor, wiring, or the valve's solenoid/mechanical parts.

2. 2

   Replace position sensor or valve section

   If the position sensor is faulty, replace it. Note that in many cases, the sensor is an integral part of the electro-hydraulic valve section and must be replaced as a complete assembly.

3. 3

   Replace valve section (if required)

   Relieve all hydraulic pressure. Label and disconnect hydraulic lines and electrical connectors. Unbolt the faulty No. 2 valve section. Install the new section with lubricated seals/O-rings, reconnect lines, and torque all bolts/fittings to manufacturer specifications.

4. 4

   Calibrate and renumber EHR

   Access the tractor's 'H' menu through the instrument cluster. Clear the old valve numbers and sequentially re-identify each valve in the stack. Recalibrate the control lever if necessary.