Case IH 127-03 - DEC – Transmission Controller (TCU) or Electronic Control Module (ECM): Transmission system pressure sensor electrical circuit fault voltage above normal

The transmission controller is detecting a voltage on the sensor's signal circuit that exceeds the expected operating range, typically indicating a Short to B+ or internal sensor failure. Note: Some lists define 127-03 as CAN C Bus Off – Short to B+.

• MAGNUM AFS Connect
• Magnum Series: 180, 190, 200, 210, 220, 225, 240, MX210, MX215
• Puma Series: 130, 145, 150, 160, 165, 170, 180, 185, 195, 200, 210, 215, 220, 230, 240
• Optum Series: 270, 300
• Maxxum Series: 110, 115, 125, 130, 140, 150, 5120-5150
• MXU Series: MXU100, MXU110, MXU115, MXU125, MXU130, MXU135
• Steiger Series: STX 325, 435

1. 1

   Check the transmission oil level. If it is low, fill it to the proper level, as low fluid can cause erratic pressure readings.

2. 2

   Inspect the transmission system pressure sensor connector and the engine-to-front wiring harness for shorts to a high voltage source.

3. 3

   Perform a jumper wire test on the circuit. If the active diagnostic code changes status when the jumper is installed, the wiring is likely intact and the sensor itself is at fault.

4. 4

   Ensure that the latest flash file/software for the application is installed in the ECM.

1. 1

   Resolve Wiring Issues

   If the diagnostic checks reveal a short to B+ in the harness, repair or replace the damaged section of the wiring harness.

2. 2

   Replace the Sensor

   If the wiring is intact, replace the faulty transmission pressure sensor using the appropriate OEM part.

3. 3

   Clear Codes

   Access the 'Trans Setup Menu' on the cab display. Retrieve, record, and clear any stored fault codes before attempting calibration.

4. 4

   Perform Transmission Calibration

   Initiate the 'CAL PRESSURE' calibration sequence. The controller will record pressure calibration points at 1500 kPa (218 PSI) and 1000 kPa (145 PSI), then command the valve to a target of 1103 kPa (160 PSI). Verify that the resulting pressure falls between 1069 to 1138 kPa (155 to 165 PSI).

5. 5

   Exit Setup

   Once the fill process is finished, press the PROG key to return to the TRANS SETUP menu, then press the DECR key to go to the TRANS EXIT menu to finalize the repair.