Case IH 2544 – UCM (Universal Control Module): Ring Sensor Critical Air Gap

The control module is detecting a critical air gap or an invalid signal from the transmission's ring gear speed sensor, preventing the module from accurately determining the transmission speed.

• Optum
• Case IH Puma 170
• Case IH Puma 185
• Case IH Puma 200
• Case IH Puma 215
• Case IH Puma 230

1. 1

   Check for other codes: If any other error codes are displayed, diagnose those first.

2. 2

   Inspect Connectors: Check the ring gear speed sensor connector (X-526), the UCM connectors (X-950 / X-951), and the wire harness connector (X-022). Ensure they are connected tightly, not damaged, and that no pins are pushed out.

3. 3

   Check for +5 Volts: Disconnect connector X-547. Turn the ignition switch ON. Measure the voltage between connector X-547 pin B (wire 7525H, Green) and ground. If +5 Volts is not indicated, repair or replace the wire harness.

4. 4

   Check for an Open Ground Circuit: Check between connector X-547 pin A (wire 60BT, Black/White) and ground. If an open circuit is indicated, repair or replace the wire harness.

5. 5

   Check for a Short to Positive Voltage: Turn the ignition switch ON. Measure the voltage between connector X-547 pin C (wire 7775, Pink) and ground. If voltage is indicated, repair or replace the wire harness.

1. 1

   Replace the Sensor

   Remove and replace the ring gear speed sensor (located on the right-hand side of the transmission housing).

2. 2

   Clear and Retest

   Clear the error code and test the tractor for normal operation.

3. 3

   Software Update

   If the fault is still present after replacing the sensor, connect the diagnostic tool and download/flash the correct level of software to the UCM.

4. 4

   Replace the UCM

   If the fault recurs after the software update, remove and replace the Universal Control Module (UCM).

5. 5

   Mechanical Inspection

   If the sensor, wiring, and UCM are all verified to be functioning properly, the transmission will need to be inspected for an internal mechanical fault (such as a damaged ring gear or a physical issue causing an excessive air gap).