Case IH 2270 (519186.03) - DEC – DEC: Synchro N Solenoid - LSD short to high voltage

The "LSD" stands for Low Side Driver. This fault indicates that the transmission/drivetrain controller has detected a "short to high voltage" (short to power) on the ground-side control circuit for the Synchronizer Neutral (Synchro N) Solenoid. This means voltage is present on the circuit where the controller expects to see a ground path, preventing the controller from properly actuating the synchronizer solenoid to shift the transmission into or out of neutral.

• MAXXUM T4E
• Puma 165
• Puma 180
• Puma 195
• Puma 200
• Puma 210
• Puma 225
• Puma 260
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Magnum Series
• Steiger Series
• CX Series
• MC Series
• MTX Series
• MX Series

1. 1

   Inspect the transmission wiring harness routing from the DEC controller to the Synchro N Solenoid for chafed wires, melted insulation, or pinched harnesses that could cause the low-side wire to short against a 12V power source.

2. 2

   Disconnect the harness at the Synchro N Solenoid and at the DEC controller.

3. 3

   With the key ON (engine OFF), use a digital multimeter to measure voltage on the low-side driver pin at the solenoid connector; if 12V is present while disconnected from the DEC, the wiring harness is shorted to power.

4. 4

   Measure the resistance across the two pins of the Synchro N Solenoid (a healthy coil typically reads around 6.8 Ohms) to check if the coil is internally shorted.

5. 5

   Inspect the pins on the DEC controller for corrosion, water ingress, or bent pins that could bridge a 12V supply pin to the LSD pin.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Solenoid

   Locate the Synchro N Solenoid on the transmission valve block (usually accessible from under the cab or through the side access panels depending on the specific tractor model).

3. 3

   Repair Wiring

   If the diagnostic checks revealed a harness short, splice and heat-shrink the damaged wire, or replace the affected transmission harness section.

4. 4

   Replace the Solenoid

   If applicable, unplug the 2-pin connector from the solenoid. Remove the retaining nut/bolt holding the solenoid coil to the valve cartridge. Slide the old coil off the valve stem. (If the entire valve cartridge is faulty, unthread the cartridge from the transmission block, being prepared to catch a small amount of hydraulic fluid). Install the new solenoid coil (or complete assembly) and tighten to OEM torque specs.

5. 5

   Reassembly

   Reconnect the electrical plug and the battery.

6. 6

   Clear Codes & Calibrate

   Turn the key ON and use the tractor's display or the Case IH Electronic Service Tool (EST) to clear the DEC fault codes. A transmission synchronizer calibration may be required after replacing transmission solenoids.