Case IH 2231 (6157.04) - DEC – DEC: Synchro 6 Solenoid - short to GND

The control module has detected a short to ground (GND) in the electrical circuit for the Synchro 6 Solenoid, meaning the voltage on the solenoid's control wire has dropped to zero (or near zero) unexpectedly. This is typically caused by a chafed wiring harness touching the chassis or an internal coil failure in the solenoid.

• MAXXUM T4E
• Case IH Maxxum (120, 130, 140, 150, 155, 175, 190)
• Case IH Magnum (315)
• Case IH Puma
• Case IH Steiger

1. 1

   Inspect the transmission wiring harness leading from the DEC module to the transmission valve block for pinched wires, melted insulation, or chafing against the tractor frame.

2. 2

   Perform component isolation by swapping the suspect Synchro 6 solenoid with a known good solenoid on the same valve block (e.g., Synchro 4 or 5). Clear the codes and cycle the key. If the fault code changes to the new location, the solenoid is internally shorted. If the 2231 (6157.04) code remains, the short to ground is in the wiring harness or the DEC module itself.

3. 3

   Perform a multimeter resistance test by disconnecting the Synchro 6 solenoid and measuring the resistance across its pins. A reading of 0 ohms (continuity to ground) confirms an internal short.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent damage to the DEC module during electrical repairs.

2. 2

   Access the Valve Block

   Locate the transmission control valve block on the side of the transmission housing. Clean the area thoroughly to prevent dirt from entering the hydraulic system.

3. 3

   Address the Wiring

   If the diagnostic checks pointed to the harness, locate the chafed section of the wire. Cut out the damaged section, solder in a new piece of wire, and seal it with dual-wall heat shrink.

4. 4

   Replace the Solenoid

   If applicable, disconnect the electrical connector from the Synchro 6 solenoid. Remove the retaining bolt or snap ring holding the solenoid in the valve block. Pull the solenoid straight out (be prepared for a small amount of transmission fluid loss). Lubricate the O-rings on the new solenoid with clean transmission fluid and press it into the valve block. Secure the retaining bolt/clip and plug in the connector.

5. 5

   Recalibrate the Transmission

   After replacing a synchro solenoid or repairing the harness, perform a transmission calibration procedure via the tractor's display monitor or H-Menu to allow the DEC to relearn the clutch and synchro engagement points.