Case IH 127-11 - DEC – DEC: Transmission system pressure sensor plausibility with engine RPM

The control module is receiving a signal from the transmission system pressure sensor that does not mathematically align with the current engine speed (RPM) driving the transmission pump.

• MAGNUM AFS Connect
• Steiger
• Magnum
• Puma

1. 1

   Check the transmission oil level. If it is low, fill it to the proper level, as low fluid will cause pressure drops at higher RPMs.

2. 2

   Inspect the transmission system pressure sensor connector and the engine RPM signal circuit. Look for wiring shorts, loose connectors, and bent pins.

3. 3

   Perform an operational load test: Watch the valve amps and the engine RPM indications in the instrumentation controller. When the amps value reaches the fill current point, a slight engine load increase or engine RPM drop should be noticed. If there is no sign of engine load increase or engine RPM drop, the master clutch may not be engaging properly, pointing to a mechanical hydraulic leak rather than a sensor failure.

1. 1

   Top Off Fluid

   Ensure the transmission hydraulic fluid is at the OEM recommended level.

2. 2

   Harness Repair

   If the diagnostic checks reveal bent pins or chafed wires on the pressure sensor harness, repair the wiring and clear the code.

3. 3

   Replace Sensor

   If the fluid level is correct, the wiring is intact, and the clutch engages mechanically but the code persists, the pressure sensor itself has internally failed and must be replaced.

4. 4

   Recalibrate

   After replacing the sensor, you must perform a Transmission Controller Calibration (CAL PRESSURE) using the tractor's display monitor or electronic service tool. The controller will record pressure calibration points at 1500 kPa (218 PSI) and 1000 kPa (145 PSI) to learn the new sensor's voltage curve.