Case IH 71 – Transmission ECM: SYNC_START_UP_INIT_ERROR 93 Auto Dis

F/R (Forward/Reverse) Synchronizer unable to change position during start-up. On tractors equipped with the 32x16 transmission, the ECM attempts to change the position of the F/R Synchronizer each time the key switch is turned to the ON or START position. If the synchronizer fails to move to the commanded position, the system logs this error and critically disables the transmission.

• JXC
• TN Series tractors

1. 1

   Verify that the Hi (Rabbit) and Lo (Turtle) transmission status lamps are flashing alternately, confirming the active F/R synchronizer fault.

2. 2

   Check the wiring between the F/R Synchronizer Solenoids and the Transmission Side Harness for disconnected plugs, or pins that are pinched, loose, or corroded.

3. 3

   Use diagnostic Mode H9 to check if the channels related to the dump solenoid, F/R Synchronizer Position Sensors, and F/R Synchronizer Solenoids are displaying the correct count.

4. 4

   Use diagnostic Mode H5 to verify the correct transition between d0 and the corresponding d value for the position sensors and solenoids.

5. 5

   Use diagnostic Mode HF to check for open circuit fault codes related to the dump solenoid, position sensors, or F/R solenoids.

1. 1

   Cycle the ignition

   Turn the ignition switch off and back on to see if the synchronizer can successfully initialize and re-enable the transmission.

2. 2

   Repair wiring

   If diagnostic checks reveal an open circuit or poor connection, repair or replace the damaged sections of the Transmission Side Harness or the solenoid connectors.

3. 3

   Replace sensors or solenoids

   If the wiring is intact but diagnostic modes (H5/H9/HF) show sensor or solenoid failure, replace the F/R Synchronizer Position Sensor or the F/R Synchronizer Solenoid.

4. 4

   Perform mechanical inspection

   If electrical components are functioning properly but the synchronizer physically cannot move, split the tractor, remove the transmission/gearbox, and inspect the internal F/R shuttle control synchronizer, shift forks, and selector sleeves for wear or seizure.