Case IH 2545 (191.01) - DEC – UCM (Universal Control Module): Wheel speed (transmission output speed) sensor - critical air gap

The control module has detected that the transmission output speed sensor is positioned too far from the inductive ring gear (tone ring) to pick up a reliable signal, or the signal is erratic/missing due to a sensor or wiring failure.

• MAXXUM T4E
• Case IH Puma series (165, 180, 195, 210, 225 CVX)
• Case IH Magnum series
• Case IH Maxxum models

1. 1

   Inspect the wiring harness and the 4-way electrical connector at the transmission output speed sensor for corrosion, pushed pins, or loose connections.

2. 2

   Verify that the sensor is fully seated against the transmission housing. Check for dirt or debris under the sensor mounting flange that could hold the sensor out too far.

3. 3

   Remove the sensor and inspect the magnetic tip for physical damage or a buildup of metallic shavings that could distort the magnetic field.

4. 4

   If the sensor and wiring are good, check for a possible mechanical fault with the speed sensor inductive ring (tone ring) inside the transmission housing.

1. 1

   Locate the Sensor

   Locate the transmission output speed sensor on the exterior of the transmission housing.

2. 2

   Disconnect and Clean

   Disconnect the electrical harness. Clean the area around the sensor base thoroughly to prevent dirt from falling into the transmission.

3. 3

   Remove the Sensor

   Remove the retaining hardware and carefully pull the sensor out of the housing.

4. 4

   Prep the Mounting Surface

   Clean the mounting bore and flange surface on the transmission. Note: It is critical that this surface is perfectly clean; any debris left behind will prevent the new sensor from seating fully, immediately recreating the "critical air gap" fault.

5. 5

   Install the Sensor

   Lubricate the new sensor seal/O-ring and insert the new transmission output speed sensor into the bore until it is completely flush.

6. 6

   Secure and Reconnect

   Tighten the retaining hardware to standard torque specifications and plug in the electrical connector.

7. 7

   Clear and Test

   Using the tractor's integrated control panel or a diagnostic service tool, clear the 2545 error code. Test drive the tractor to ensure the UCM registers the transmission output speed and the system operates normally.