Case IH 56071 – Transmission Controller (TRANS): No Voltage to 4F or 4R Valves due to Neutral Relay or Bottom of Clutch Relay Fault

The transmission controller monitors the 4F (Forward) and 4R (Reverse) clutch solenoid circuits. If the controller detects that the voltage is lower than expected, it indicates that the circuit is open, shorted to ground, or has lost its power supply. The 4F and 4R solenoids receive their switched power via the Bottom of Clutch (BOC) relay and the Transmission Neutral Latch relay.

• STX Steiger
• MX Series Magnums
• MX200
• MX220
• MX270
• Puma Series
• Steiger / STX Series

1. 1

   Check for accompanying codes: If TRANS 56016 or TRANS 56086 are present, they can pinpoint the root cause. If 56071 is active, it must be troubleshot first.

2. 2

   Inspect mechanical linkages: Check the inching (clutch) pedal, its position potentiometer, and the Bottom of Clutch (BOC) switch assembly. Ensure the mechanical installation is tight and properly adjusted.

3. 3

   Test the relays: Locate the transmission neutral latch relay (often Relay #17) and the neutral relay (often Relay #16). Ensure all terminals are properly seated. With the key switch ON and Relay #16 removed, verify voltage is present at cavity 3.

4. 4

   Check grounds: Inspect and clean all ground wires and cables connecting the transmission controller and cab solenoids, as poor grounds are a notorious cause of this code.

1. 1

   Clean Ground Connections

   Start with the simplest electrical fix. Clean the ground connections where the cab solenoids connect, and verify the transmission controller ground is secure.

2. 2

   Relay Replacement

   If the neutral latch relay or bottom of clutch relay fails testing, replace them with new relays. Ensure the relay block cavities are not pushed out or corroded.

3. 3

   Pedal Recalibration

   If the inching pedal potentiometer, stop bolt, or BOC switch were loose and had to be tightened (or replaced), you must perform the clutch pedal adjustment procedure. Afterward, run the pedal calibration procedure in the 'TRANS SETUP' menu through the instrumentation controller.

4. 4

   FNRP Module Replacement (If Applicable)

   If the tractor refuses to go into gear and throws code 56071 alongside 56086, the Forward/Neutral/Reverse/Park (FNRP) module is likely at fault. Replace the FNRP module. When installing the updated module, you must add a dedicated ground wire from the extra terminal on the back of the module directly to the cab ground.

5. 5

   Clear and Test

   Clear the fault codes, cycle the key switch, and operate the tractor to verify the voltage has been restored to the 4F/4R valves.