John Deere 521931.05 – GPM (Gear Shift Module): Gear 5 Solenoid Current Too Low

This diagnostic trouble code is generated when the control software detects that the electrical current value at the Gear 5 solenoid valve is too low. This condition typically indicates an open circuit in the solenoid coil itself or in the wiring harness supplying power to it. When this fault is active, the transmission will have limited or no functionality, and the tractor may fail to engage 5th gear.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6135R
• 6140R
• 6150R
• 6170R
• 6190R
• 6210R
• 6230R
• 6250R

1. 1

   Inspect the wiring harness running from the GPM to the DirectDrive transmission control block for chafed wires, broken lines, or disconnected plugs.

2. 2

   Disconnect the connector at the Gear 5 solenoid valve and check for corrosion, bent pins, or moisture intrusion.

3. 3

   Using a multimeter, measure the resistance across the pins of the Gear 5 solenoid coil (an infinite/OL reading confirms the coil is internally open).

4. 4

   With the key ON, verify that the GPM is sending the appropriate voltage signal to the solenoid connector when Gear 5 is commanded.

1. 1

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

2. 2

   Locate the transmission solenoid control block on the DirectDrive transmission housing.

3. 3

   Identify the specific solenoid valve assigned to Gear 5.

4. 4

   If the diagnostic checks revealed damaged wiring or a faulty connector, repair the harness or splice in a new connector pigtail.

5. 5

   If the wiring is intact but the solenoid coil failed the resistance test, remove the retaining nut/bolt securing the Gear 5 solenoid coil to the valve cartridge.

6. 6

   Slide the old solenoid coil off the valve stem.

   If the entire cartridge valve is faulty, drain the transmission fluid below the valve level, unthread the cartridge, and install a new one.

7. 7

   Slide the new solenoid coil onto the valve and secure it.

8. 8

   Reconnect the electrical harness.

9. 9

   Clear the GPM 521931.05 fault code using a diagnostic scan tool or the CommandCenter display.

10. 10

    Test drive the tractor, shifting through the ranges to ensure Gear 5 engages smoothly and the code does not return.