Case IH 2412 – Transmission Control Module (Transmission ECU): Synchroniser did not engage previous range after error code 2403 or 2405

This is a cascading error specific to Semi-Powershift (SPS) transmissions. When the transmission attempts a range shift and the synchronizer mechanically or electrically fails to disengage the current range (logging 2403/2405), the system's safety protocol attempts to revert and re-engage the previous range. If it fails to engage that previous range as well, it logs code 2412.

• Optum
• Puma
• Maxxum
• MXM
• Steiger
• Magnum
• T6000
• T7000
• T7

1. 1

   Check for accompanying potentiometer codes (2415 through 2420). If present, the sensor is likely the culprit rather than the mechanical synchronizer.

2. 2

   Enter the tractor's H-Menu diagnostics to view live potentiometer readings during a shift attempt to verify if the sensor is tracking movement.

3. 3

   Inspect the wiring harnesses leading to the transmission synchronizer solenoids and rotary position sensors for damage, corrosion, or unplugged connectors.

1. 1

   Potentiometer Replacement

   If diagnostics point to a failed rotary position sensor, locate the synchronizer potentiometer on the side of the transmission housing. Disconnect the harness, unbolt the sensor, and install the replacement.

2. 2

   Mechanical Repair

   If the sensors and solenoids are functioning properly, the synchronizer rings or shift forks inside the transmission are likely worn, burnt, or physically jammed. This requires splitting the tractor to access the transmission gear shafts and replacing the synchronizer assembly.

3. 3

   Transmission Calibration

   Any time a potentiometer is replaced, a mechanical repair is effected, or the non-volatile memory is reset, you must perform the H1 Clutch and Synchroniser Calibration. Ensure the transmission oil temperature is between 20°C and 50°C. Apply the parking brake, turn off the A/C, and deselect all electrical/hydraulic services. Enter the H1 calibration mode by holding the High and Low range buttons and starting the engine. Set engine speed to 1200 RPM and follow the on-screen prompts until 'END' is displayed.