Case IH 3664 – ENGINE: EGR command saturation over lower threshold

The engine control unit is commanding the Exhaust Gas Recirculation (EGR) valve to move to a specific position, but the valve is physically failing to reach that position. This is most commonly caused by heavy soot/carbon buildup causing the valve to stick mechanically, or a failure/mismatch in the valve's internal position sensor.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Farmall 65C
• Farmall 75C
• Farmall 90C
• Farmall 100C
• Farmall 110C
• Farmall 120C
• Maxxum series tractors
• Puma series tractors

1. 1

   Check for Multiple Codes: Verify if other EGR-related codes are present (such as 3665, 3666, 3667, or 3675). Codes like 3667 or 3669-3672 indicate electrical open or short circuits, which would point to a wiring issue rather than a mechanically stuck valve.

2. 2

   Inspect the Wiring Harness: Disconnect the EGR valve connector and inspect for bent pins, spread pins, corrosion, or signs of water/oil intrusion.

3. 3

   Check Battery Voltage: Ensure the system voltage is stable, as severe voltage fluctuations can sometimes disable power stage diagnostics and throw false EGR codes.

4. 4

   Mechanical Inspection: Remove the EGR valve and inspect the internal flap/pintle. If it is heavily caked in hard carbon and cannot move freely, the valve is mechanically bound.

1. 1

   Preparation

   Turn the ignition OFF and disconnect the negative battery cable.

2. 2

   Drain Coolant (If Applicable)

   Depending on the specific FPT engine configuration, you may need to drain a small amount of engine coolant if the EGR valve housing integrates with the EGR cooler water lines.

3. 3

   Removal

   Disconnect the electrical harness from the EGR valve actuator. Remove the mounting bolts securing the EGR valve to the exhaust manifold and EGR cooler.

4. 4

   Cleaning

   Clean the mating surfaces on the manifold and cooler, ensuring no old gasket material or carbon chunks fall into the intake or exhaust tracts.

5. 5

   Installation

   Install the new EGR valve using new gaskets and O-rings. Torque the mounting bolts to OEM specifications. Reconnect the coolant lines and the electrical harness.

6. 6

   Restore Self-Learning Parameters

   According to the FPT/CNH service manual, after replacing the EGR valve, you must use the Case IH Electronic Service Tool (EST) to perform the 'Reset ECU data (EGR valve)' procedure. This forces the Engine ECU to relearn the new valve's end stops and self-learning parameters.

7. 7

   Finalize

   Reconnect the battery, clear the inactive fault codes, and test run the engine to ensure the code does not return.