Case IH 517962-01 - DEC – Transmission Controller (TCU / TRANS): Transmission low clutch solenoid electrical circuit fault voltage low

The controller is detecting a "voltage low" condition, which typically means the circuit is either open, shorted to ground, or drawing current below the acceptable limit. If the issue is temperature-sensitive, it often points to the solenoid coil beginning to fail internally.

• MAGNUM AFS Connect
• Case IH Magnum Series
• MX series
• Magnum 235-340 Series 4
• Magnum 260

1. 1

   Remove the controller cover from the rear of the tractor and visually inspect the wiring harness running from the transmission controller toward the solenoids located under the cab for any chafing or damage.

2. 2

   Perform a harness resistance test by disconnecting connector C355 from the transmission controller and measuring resistance between cavity 14 and cavity 18 on the wiring harness side (should be approximately 10 ohms).

3. 3

   Perform a short-to-ground test by measuring resistance between cavity 14 of connector C355 and chassis ground, and then cavity 18 to chassis ground (less than a few ohms indicates a short to ground).

4. 4

   Perform a direct solenoid test by lifting the cab to access the transmission solenoids, disconnecting the low clutch solenoid connector (C036), and measuring resistance directly between pin 1 and pin 2 of the solenoid (should be around 10 ohms).

1. 1

   Safely park the tractor, turn off the engine, and ensure the transmission is in park.

   Safely park the tractor, turn off the engine, and ensure the transmission is in park.

2. 2

   If the diagnostic tests above prove the solenoid is faulty (resistance is not ~10 ohms or it is internally shorted to the solenoid case), prepare to replace the solenoid.

   If the diagnostic tests above prove the solenoid is faulty (resistance is not ~10 ohms or it is internally shorted to the solenoid case), prepare to replace the solenoid.

3. 3

   Lift/tilt the cab according to the OEM service manual to gain access to the transmission valve block.

   Lift/tilt the cab according to the OEM service manual to gain access to the transmission valve block.

4. 4

   Clean the area around the low clutch solenoid to prevent debris from entering the transmission valve body.

   Clean the area around the low clutch solenoid to prevent debris from entering the transmission valve body.

5. 5

   Disconnect the electrical connector (C036) from the low clutch solenoid.

   Disconnect the electrical connector (C036) from the low clutch solenoid.

6. 6

   Remove the retaining hardware and extract the faulty low clutch solenoid.

   Remove the retaining hardware and extract the faulty low clutch solenoid.

7. 7

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

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

8. 8

   Install the new solenoid valve into the valve block and secure it.

   Install the new solenoid valve into the valve block and secure it.

9. 9

   Reconnect the electrical harness, lower the cab, and clear the fault codes from the TCU. Test drive to ensure the clutch engages properly and the code does not return.

   Reconnect the electrical harness, lower the cab, and clear the fault codes from the TCU. Test drive to ensure the clutch engages properly and the code does not return.