Case IH 44 – Transmission ECM: Synchronizer Hi-Lo (Forward) Solenoid has a short to ground or an open circuit

The system logs this code when the tractor is started and the Power Shuttle Forward/Neutral/Reverse (FNR) lever is in the neutral position, but the controller detects an electrical fault in the forward solenoid's circuit. This prevents the transmission from properly engaging the forward clutch pack.

• MX Maxxum
• JX series
• JXU series
• Farmall 75C
• Farmall 85C
• Farmall 85U
• Farmall 105U
• TN60A
• TN70A
• TN75A
• TNDA
• TNSA

1. 1

   Inspect the wiring harness for a short to ground or an open circuit between ECM connector 1, pin 16 and the forward solenoid coil terminal.

2. 2

   Test the return circuit for a short across the solenoid coil terminals, or a short/open between the solenoid coil terminal and ECM connector 1, pin 4.

3. 3

   Ohm-test the Synchronizer Hi-Lo (Forward) Solenoid Coil to determine if the coil itself has failed internally.

4. 4

   If the wiring and solenoid test good, check for a failed internal ECM driver (open or shorted to ground).

5. 5

   If available, use the Electronic Service Tool (EST) or the tractor's onboard H9 diagnostic mode (channel 12) to verify the electrical counts/signal to the solenoid.

1. 1

   Park the tractor on a level surface, turn off the engine, and ensure the Power Shuttle FNR Lever is in the neutral position.

2. 2

   Locate the Power Shuttle Control Valve.

   On most configurations (like the 32x16 transmission), the Synchronizer Shuttle (Reverse) and Hi-Lo (Forward) Solenoids are located on the bottom of the Power Shuttle Control Valve block.

3. 3

   Disconnect the wiring harness from the Forward Solenoid.

4. 4

   Using a multimeter, perform the continuity and short-to-ground checks on the harness back to ECM Connector 1 (Pins 16 and 4).

   Repair any rubbed, broken, or melted wires.

5. 5

   If the harness is intact, remove the retaining nut/bolt holding the Forward Solenoid coil to the valve spool.

6. 6

   Slide the faulty solenoid coil off the valve cartridge and replace it with a new OEM coil.

7. 7

   Reconnect the wiring harness.

8. 8

   Start the tractor and cycle the Power Shuttle FNR Lever or Clutch Pedal to re-enable the transmission.

   Verify that the Transmission Status Lamp has stopped flashing and that the tractor engages forward gear smoothly.

9. 9

   If the code persists and the wiring/solenoid are brand new, the Transmission ECM will need to be replaced and reprogrammed.