Case IH 19027 (DTC 329C) - ECU – Engine Control Unit (ECU): Exhaust flap actuator supply voltage is out of range

The system has detected an electrical or mechanical failure of the exhaust flap actuator. The fault is often flagged via the CAN-Reception-Structure, meaning the module is receiving implausible voltage data or CAN timeout errors from the actuator's intelligent device.

• MAXXUM T4E
• Case IH 240 Series Axial-Flow Combines
• Case IH Vestrum Series Tractors (Vestrum 100, 110, 120, 130)
• Machines equipped with the NEF 4-Cylinder Engine
• Case IH CR/CX Series Combines

1. 1

   Use a multimeter to check the supply voltage at the exhaust flap actuator connector to verify if it is out of range compared to system battery voltage.

2. 2

   Inspect the wiring harness between the Engine ECU and the exhaust flap actuator for chafing, shorts to ground, or open circuits. Check the connector pins for corrosion or water ingress.

3. 3

   Verify the integrity of the CAN High and CAN Low communication lines at the actuator.

4. 4

   Check if the exhaust flap is physically stuck, as mechanical binding can cause the actuator motor to draw abnormal current/voltage.

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the Actuator

   Locate the exhaust flap actuator (also referred to as the exhaust brake valve) on the engine's exhaust system.

3. 3

   Manage Coolant (If Applicable)

   On NEF 4-cylinder engines, the exhaust flap actuator is cooled by engine coolant. Clamp the coolant lines leading to the actuator or drain the coolant partially to prevent spills.

4. 4

   Removal

   Disconnect the electrical harness from the actuator. Disconnect the coolant lines. Unbolt the actuator assembly from the exhaust piping.

5. 5

   Installation

   Mount the new exhaust flap actuator and tighten the mounting bolts to OEM specifications.

6. 6

   Reconnection

   Reattach the coolant lines and plug in the electrical connector.

7. 7

   Fluid Check

   Top off the engine coolant to replace any fluid lost during the swap.

8. 8

   Clear Codes

   Reconnect the battery. Use a diagnostic service tool to clear the inactive 19027 / 329C fault codes. Start the engine, let it idle, and verify that the code does not return and that there are no exhaust or coolant leaks.