Case IH 2506 (5937.17) - DEC – Transmission Control Module (TCU): Clutch B pressure not plausible (mismatch between clutch B pressure and solenoid current)

This fault indicates that the transmission controller is commanding a specific electrical current to the Clutch B proportional solenoid, but the resulting hydraulic pressure (as read by the pressure sensor) does not match the expected value for that current. This mismatch typically points to a mechanical/hydraulic issue with the valve itself (such as a stuck valve), a wiring harness issue, or a failed solenoid coil.

• VESTRUM CVX
• Case IH Magnum Series (MX210, MX230, MX255, MX285, 215-335)
• Case IH Puma Series (115 through 240, 165, 180, 195, 210, 225)
• Case IH Maxxum Series (100 through 150, MXM models)

1. 1

   Check for Active Codes: If any other transmission or electrical error codes are displayed alongside 2506, troubleshoot those codes first.

2. 2

   Visual & Physical Inspection: Check the Clutch B solenoid connector (designated as X-528) and the dump solenoid connector (X-545). Ensure the connectors are firmly connected, not damaged, and that the pins are seated in the correct positions.

3. 3

   Resistance Testing: Test the high range / Clutch B solenoid coil. Using a multimeter, measure the resistance between solenoid terminal 1 and terminal 2.

4. 4

   Verify Specifications: The resistance indicated should be between 8 to 11 Ohms. (Note: Always account for the internal resistance of your multimeter leads when testing).

1. 1

   Isolate the Circuit

   Disconnect the wiring harness from the Clutch B solenoid to prevent damage to the Transmission Controller.

2. 2

   Test the Solenoid

   Perform the 8-11 Ohm resistance check across the solenoid pins.

3. 3

   Replace if Out of Spec

   If the resistance falls outside of the 8-11 Ohm range, or if the solenoid is mechanically stuck (causing the pressure mismatch), remove and replace the Clutch B solenoid valve.

4. 4

   Check Wiring (If Solenoid is Good)

   If the solenoid tests within specification, inspect the wiring harness between the TCU and the solenoid for shorts to ground or open circuits, and verify the pressure sensor is functioning correctly.

5. 5

   Recalibrate

   After replacing transmission solenoids or resolving the fault, the transmission clutches will require recalibration. (Failure to do so will result in codes such as 2028 or 2363: 'Clutch B not calibrated').