Case IH 56090 – Transmission Controller (TRANS): Trans Neutral Latch Relay Coil circuit is open or shorted to ground when commanded

The transmission control relay has failed open, or the clutch solenoid circuit of the speed reducer has failed open or is short-circuited to the ground connection.

• STX Steiger
• Case IH Steiger series
• Case IH Puma series
• Case IH MX Magnum series

1. 1

   Check for related codes: If fault code TRANS 56088 or 56090 occurs alongside TRANS 56072, troubleshoot 56088 or 56090 first.

2. 2

   Monitor relay function via display: Turn the key switch to the ON position and enter 'TRANS VIEW' on the instrumentation controller. Navigate to 'SW #2'. With the transmission control lever in the park position, monitor the status of the neutral latch relay (lockup common) circuit.

3. 3

   Inspect the relay block: Remove the transmission neutral latch relay (relay #16 or #17) and verify that all terminals are properly inserted into the relay block and are not loose or pushed out.

4. 4

   Check for voltage: With the key switch in the ON position and the neutral relay removed, measure the voltage at the relay block (e.g., cavity 3 of the relay receptacle) to ensure power is reaching the circuit.

1. 1

   Locate fuse panel

   Turn off the tractor and locate the load center/fuse panel.

2. 2

   Remove relay

   Identify and remove the Transmission Neutral Latch Relay (refer to your specific model's fuse panel diagram, often relay #16 or #17).

3. 3

   Inspect and repair wiring

   Inspect the relay block terminals for corrosion, damage, or loose connections. Repair any wiring harness issues if the circuit is shorted to ground or open.

4. 4

   Replace relay

   If the wiring and voltage checks pass, the relay itself has likely failed or become weak. Replace the transmission neutral latch relay with a new OEM relay.

5. 5

   Verify repair

   Turn the key switch to the ON position, clear the fault codes, and use the 'TRANS VIEW' screen on the instrumentation controller to verify the relay is now functioning properly when commanded.