Iveco 118 – Transmission Control Unit (TCU): Clutch does not turn off

The automated system is attempting to disengage the clutch to interrupt engine torque, but the clutch actuator is failing to move, or the clutch travel sensor is not registering the movement. This prevents the transmission from safely shifting gears.

• Iveco Stralis (AT / AD)
• Iveco Trakker
• Iveco EuroTech
• Iveco EuroStar

1. 1

   Verify that there is adequate pneumatic air supply to the clutch valves and actuator

2. 2

   Use a diagnostic tool to check the clutch travel sensor values (signal for absolute clutch stroke with clutch closed should be < 24mm)

3. 3

   Inspect the peripheral clutch parts for mechanical binding, such as a jammed or broken release bearing, or a cracked/broken release fork

4. 4

   Check if the clutch actuator push rod is properly attached and adjusted, as an incorrect push rod length can trigger engagement/disengagement faults

1. 1

   Removal

   Disconnect the air supply and electrical connectors to the clutch actuator. Remove the actuator from the transmission housing.

2. 2

   Inspection & Cleaning

   Inspect the clutch installation space. Clean the area and check the release fork and release bearing. Lightly grease the release fork driving points and the release bearing (using a specified grease like OLISTA Longtime 3EP).

3. 3

   Push Rod Adjustment

   Measure the distances between the clutch lever ball socket, the back face of the actuator, and the depth of the pressure sleeve. Calculate the required rod length using the manufacturer formula: L = A - B + C + D (where D is the maximum stroke of the clutch actuator, exactly 33 mm). Twist the ball head on the push rod until the exact calculated length is reached. Tighten the locking nut to 52 Nm.

4. 4

   Installation

   Install the newly adjusted clutch actuator onto the transmission and reconnect the pneumatic lines and electrical harnesses.

5. 5

   Clutch Calibration (Teach-in)

   Program the clutch using an Iveco-compatible diagnostic tool (like Iveco E.A.S.Y. or TEXA). The exact engagement and disengagement points of the new setup are no longer recognized by the electronics. Run the 'clutch teach-in process' so the TCU learns the new parameters. Failing to do this will result in immediate fault codes upon engine startup.