John Deere 736.05 – Transmission Control Unit (TCU): Current Too Low or Open Circuit in Transmission Solenoid Circuit

The control unit has detected that insufficient current is flowing to the solenoid valve, which prevents it from functioning correctly and can lead to issues with gear selection or transmission performance.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5085M
• 5090M
• 5095M
• 5100M
• 5105M
• 5115ML
• 6230
• 6330
• 6430
• 7720
• 7810
• 7820
• 7920
• 7230
• 8R Series Tractors
• 210L EP Tractors
• 310SJ
• 410J Backhoe Loaders

1. 1

   Visually inspect the wiring harness and connectors leading to the specific transmission solenoid for signs of damage, loose connections, or corrosion.

2. 2

   Use a multimeter to check for open circuits or high resistance in the wiring between the Transmission Control Unit and the solenoid valve.

3. 3

   Verify that the electrical supply voltage to the solenoid is within the correct OEM specification range.

4. 4

   Perform a diagnostic resistance test on the proportional solenoid valve itself to determine if the internal coil has failed or has an open circuit.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical shorts while working on the transmission control system.

2. 2

   Locate the Solenoid

   Access the transmission valve block and locate the affected solenoid (Proportional Solenoid Valve for Clutch Side Shaft 2 / Y40 Gear Selector Solenoid).

3. 3

   Repair Wiring (If Applicable)

   If the diagnostic checks revealed a broken wire, chafed harness, or corroded connector, repair or replace the affected wiring segment.

4. 4

   Replace the Solenoid (If Defective)

   If the wiring is intact but the solenoid failed the multimeter test, remove the retaining hardware and extract the faulty solenoid valve. Install the new OEM replacement solenoid and torque to factory specifications.

5. 5

   Reassemble and Reconnect

   Reconnect the electrical harness to the new solenoid, ensuring the connector is fully seated and locked. Reconnect the battery.

6. 6

   Reset and Test

   Clear the active 000736.05 fault code using a John Deere diagnostic tool (or by restarting the system if it clears automatically). Test the transmission by shifting through the gears to ensure the error code does not return and the clutch engages properly.