Case IH 2118 (6156.17) - DEC – DEC: Synchro 5 Solenoid Short to GND

The Drivetrain Electronic Controller (DEC) has detected a "short to GND" (short to ground) on the Low Side Driver (LSD) circuit that controls the Synchro 5 Solenoid. This means the electrical path that grounds the solenoid to activate it is permanently shorted to the chassis or ground wire, which can prevent the transmission from properly shifting into or out of the gear ranges controlled by the 5th synchronizer.

• MAXXUM T4E
• Case IH and New Holland tractors equipped with powershift or semi-powershift transmissions that utilize electronic synchronizer solenoids

1. 1

   Inspect for a loose connector or bent pins at the Synchro 5 solenoid and at the DEC/TCU harness

2. 2

   Inspect the wiring harness between the DEC and the Synchro 5 solenoid for damaged wiring (chafing or melting) that could cause the circuit to short to the tractor's frame/ground

3. 3

   Test the Synchro 5 solenoid coil for an internal failure (internal short to ground)

4. 4

   If the wiring and solenoid test good, check for a TCU/DEC internal failure on the Low Side Driver circuit

1. 1

   Disconnect Battery

   Always disconnect the negative battery terminal before servicing transmission electronics.

2. 2

   Locate the Solenoid

   Locate the Synchro 5 solenoid on the transmission control valve block.

3. 3

   Disconnect and Inspect

   Unplug the harness connector from the solenoid. Inspect both sides of the connector for corrosion, moisture, or bent pins.

4. 4

   Test the Solenoid

   Use a multimeter to measure the resistance across the solenoid pins, and from the pins to the solenoid housing. If there is continuity to the housing, the solenoid has failed internally and must be replaced.

5. 5

   Test the Harness

   With the DEC and solenoid disconnected, test the LSD wire in the harness for continuity to ground. If continuity is found, trace the harness to locate and repair the chafed/damaged wire.

6. 6

   Reassemble and Clear Codes

   Once the wiring is repaired or the solenoid is replaced, reconnect all components, reconnect the battery, and clear the fault codes using the diagnostic interface.