Case IH 2323 – Transmission Control Module (TCU): Transmission mid speed sensor - open circuit

The controller is detecting infinite resistance (a broken electrical path) on the circuit belonging to the mid-range/average transmission speed sensor. This prevents the controller from reading the rotational speed of the mid-gears, which can result in disabled shifting, clutch slippage, or the transmission defaulting to a limp mode.

• Puma/Mid Range Magnum
• Steiger
• Magnum (MX/TG series)
• Puma
• Maxxum series
• T6000
• T7
• TM
• TS series

1. 1

   Inspect the wiring harness leading to the mid/average transmission speed sensor on the transmission housing for severed wires, rodent damage, or a disconnected plug.

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Using a multimeter, measure the resistance across the pins of the sensor itself. A healthy Case IH magnetic speed sensor typically reads between 2,700 and 3,300 ohms. If the multimeter reads 'O.L.' (Open Loop) or infinite resistance, the sensor has failed internally and must be replaced.

4. 4

   If the sensor tests good, turn the tractor key to the 'RUN' position. Check for a 5 VDC reference voltage at the harness connector. Check the ground circuit for continuity to a clean chassis ground. If voltage or ground is missing, trace the harness back to the transmission controller to locate the break.

1. 1

   Preparation

   Park the machine on a level surface, engage the parking brake, turn off the engine, and disconnect the battery to protect the transmission controller.

2. 2

   Locate the Sensor

   Locate the mid/average transmission speed sensor on the side of the transmission housing.

3. 3

   Removal

   Disconnect the electrical harness from the sensor. Thoroughly clean the area around the sensor base to prevent dirt or debris from falling into the transmission sump. Remove the retaining bolt or snap ring holding the sensor in place and pull the sensor straight out.

4. 4

   Installation

   Lightly lubricate the O-ring on the new transmission speed sensor with clean transmission fluid. Insert the new sensor into the housing and secure it with the retaining hardware.

5. 5

   Reconnection

   Reconnect the electrical harness, ensuring the locking tab clicks into place. Reconnect the tractor's battery.

6. 6

   Clear Fault Codes

   Turn the key ON. Access the tractor's diagnostic menu (on Puma/Magnum models, this is often done via the 'H Menu' on the instrument cluster). Navigate to the H8 or HC menu to clear stored EEPROM error codes and reset the system.

7. 7

   Test

   Perform a test drive to ensure the transmission shifts smoothly and the 2323 code does not return.