Case IH PC8 – Transmission Control Unit (TCU) / Power Control Unit (PCU): No Signal From The Engine Torque/RPM Sensor

The control module is receiving no electrical signal from the Engine Torque/RPM Sensor, which can result in erratic shifting, loss of speedometer readouts, or clutch slipping faults.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• Puma 130 through 240
• Puma CVX
• Maxxum 110
• Maxxum 115
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Maxxum 150
• Magnum 180 through 380
• MXU 100 through 135

1. 1

   Check the sensor's molded female socket interface and wiring harness for corrosion, moisture, or damaged pins. Look for an open circuit or a short to ground.

2. 2

   Ensure the Engine Torque/RPM sensor has not been accidentally swapped with the transmission mid-speed or output speed sensors during previous maintenance.

3. 3

   Check the flywheel damper spring and ring gear for physical damage or debris that might prevent the magnetic inductive sensor from reading the rotational velocity.

1. 1

   Preparation

   Power down the tractor, place all shift levers in neutral, lower any attached equipment to the ground, and block the wheels (front and rear).

2. 2

   Locate the Sensor

   Find the Engine Torque/RPM sensor, which is positioned directly over the engine flywheel ring gear / transmission input area.

3. 3

   Removal

   Disconnect the sealed electrical connector from the sensor. Remove the retaining hardware and extract the faulty magnetic inductive sensor from its housing.

4. 4

   Installation

   Install the new heavy-duty magnetic inductive speed sensor into the housing and secure the retaining bolt.

5. 5

   Reconnection

   Reconnect the electrical wiring harness, ensuring the weather-tight seal is fully seated.

6. 6

   Calibration

   Clear the fault codes from the PCU non-volatile memory. Perform a Transmission/Clutch Calibration setup procedure. For MXM series, this involves holding the High and Low range buttons while starting the engine until 'CAL' appears on the transmission display, setting the engine speed to 1200 RPM, and following the on-screen prompts to recalibrate the clutch engagement times.