Case IH 518391-04 - DEC – DEC: Park brake detent solenoid voltage below normal or shorted to low source

The controller is detecting abnormally low voltage on the park brake detent solenoid circuit, meaning the solenoid cannot stay magnetized to hold the valve open. When this circuit fails, the tractor will often abruptly lock up and drop into park, even at road speeds.

• MAGNUM AFS Connect
• Magnum 235
• Magnum 260
• Magnum 275
• Magnum 290
• Magnum 315
• Magnum 340
• Magnum 370
• Magnum 380
• Steiger 470
• Steiger 540
• Steiger 600
• Quadtrac 470
• Quadtrac 540
• Quadtrac 600

1. 1

   Inspect the Solenoid Coil: Visually inspect the park brake solenoid coil for a cracked plastic casing, which causes it to short out or fail to stay magnetized.

2. 2

   Check the Wiring Harness: Inspect the electrical connector (Connector 49 or 49M) and the chassis harness leading to the transmission control valve for rubbing, breaks, or shorts to ground.

3. 3

   Pressure Test: Verify if regulated transmission pressure drops when the Forward/Neutral/Reverse (FNRP) lever is pulled out of park, which may indicate a failed check valve in the park circuit suction line.

1. 1

   Access the Solenoid

   Locate the park brake detent solenoid on the transmission control valve assembly. Note: On Magnum tractors, you may need to remove the rear tire to properly access the valve block.

2. 2

   Disconnect the Battery

   Ensure the machine is powered off and batteries are disconnected to prevent further electrical shorts.

3. 3

   Remove the Connector

   Unplug the 2-pin electrical connector from the park brake solenoid.

4. 4

   Remove the Solenoid Coil

   Remove the retaining nut holding the solenoid coil to the valve stem and slide the cracked/failed coil off.

5. 5

   Install the New Part

   Slide the updated replacement coil onto the valve stem and secure it.

6. 6

   Reconnect and Clear Codes

   Plug the 2-pin connector back in, re-install the tire (if removed), power up the tractor, and clear the DEC fault codes. Test the FNRP lever to ensure the park brake releases and engages without throwing the code.