John Deere 738.05 – PTQ: Solenoid valve for changing range H1 (A-B), intensity too low / Four-Speed Solenoid 3 (B3 - C4) Circuit Fault

The control module has detected that the electrical current flowing through the gear selector range solenoid circuit is below the minimum expected threshold. This typically indicates an open circuit, which is most commonly caused by a disconnected wiring harness, a broken wire, corroded connector pins, or a burned-out internal solenoid coil.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6010
• 6110
• 6210
• 6310
• 6410
• 6510
• 6610
• 6810
• 6910
• 7185J
• 7195J
• 7205J
• 7210J
• 7225J
• 7715
• 7815
• 7720
• 7820
• 7920

1. 1

   Inspect the wiring harness leading to the transmission valve body for snagged, rubbed, or broken wires.

2. 2

   Disconnect the harness at the affected range solenoid (H1 / A-B). Check for water intrusion, dirt, or corroded pins, then reconnect it to ensure it is seated tightly.

3. 3

   Using a multimeter, measure the resistance across the pins of the solenoid coil. If the multimeter reads 'OL' (infinite resistance), the internal coil is broken (open) and the solenoid must be replaced.

4. 4

   If the solenoid tests within specification, disconnect the harness at the PTQ controller and test the specific circuit wires for continuity between the module and the solenoid plug.

1. 1

   Park and prepare machine

   Park the tractor on a level surface, engage the parking brake, lower all implements, and turn off the engine.

2. 2

   Disconnect battery

   Disconnect the negative battery cable to prevent electrical shorts during the repair.

3. 3

   Locate valve block

   Locate the transmission control valve block (usually mounted on the side of the transmission housing).

4. 4

   Identify faulty solenoid

   Identify the specific range solenoid logging the fault (Range H1 / Solenoid 3). Consult your specific model's technical manual diagram to ensure you are pulling the correct valve.

5. 5

   Disconnect harness

   Disconnect the electrical connector from the solenoid.

6. 6

   Remove retaining hardware

   Remove the retaining nut or mounting bolts securing the solenoid coil/cartridge to the valve body.

7. 7

   Remove faulty solenoid

   Carefully pull the faulty solenoid valve out of the bore. Have a catch pan ready, as a small amount of transmission fluid will leak out.

8. 8

   Inspect and clean bore

   Inspect the valve body bore for any debris or scoring. Clean the area with a lint-free cloth.

9. 9

   Lubricate O-rings

   Lubricate the O-rings on the new solenoid valve with clean John Deere transmission fluid.

10. 10

    Install new solenoid

    Insert the new solenoid into the bore, ensuring it seats fully. Install and tighten the retaining hardware to the OEM torque specification.

11. 11

    Reconnect harness

    Reconnect the electrical harness until the locking tab clicks.

12. 12

    Test and verify

    Reconnect the battery, start the tractor, and cycle the transmission through all ranges to verify the fault code is cleared and normal shifting is restored. Check for fluid leaks around the new valve.