Case IH 2668 (6156.11) - DEC – Transmission Control Module (TCU): Synchro 5 Solenoid Generic Error

A malfunction associated with the Synchro 5 Solenoid, an electro-hydraulic valve responsible for actuating the 5th synchronizer gear/range in the transmission. This can be caused by an open circuit, a short to 12V, or the synchronizer no longer being engaged.

• MAXXUM T4E
• 9282
• 9482
• 9682
• 9882
• T-TL-TLA-TS-TSA-T5000-T6000 series

1. 1

   Check the wiring harness between the Transmission Control Module and the Synchro 5 solenoid for an open circuit or a short to 12V.

2. 2

   Check if related codes (like 2081 '4/5 Synchro Potentiometer signal too high' or 2082 'signal too low') are present, which would indicate a sensor failure rather than a solenoid failure.

3. 3

   Verify that the transmission oil is up to operating temperature (above 5°C) and system pressure is adequate to move the shift spools.

1. 1

   Locate the Solenoid

   Locate the transmission control valve block. On the 82 series powershift models, this is located on the transmission housing (referenced in service diagrams as the 1402 Powershift Solenoid Valve assembly).

2. 2

   Inspect the Harness

   Disconnect the electrical connector at the Synchro 5 solenoid. Inspect the pins for corrosion, pushed-back terminals, or wire chafing.

3. 3

   Test the Solenoid Coil

   Use a multimeter to measure the resistance across the solenoid coil pins. If the circuit is open (infinite resistance) or shorted, the solenoid must be replaced.

4. 4

   Inspect the Valve Spool

   If the coil tests within specification, remove the solenoid cartridge from the valve body. Inspect the spool for debris, scoring, or sticking, which can cause the 'Synchro 5 no longer engaged' mechanical error.

5. 5

   Replace and Calibrate

   Install the new solenoid or cleaned valve. Reconnect the harness. Use a diagnostic tool (or Can-Bus DTC Eraser) to clear the inactive fault codes, then perform a transmission clutch and synchronizer calibration procedure, as the TCU needs to relearn the fill times for the new solenoid.