Case IH 3647 (DTC 1338) - ECU – Engine Control Unit (ECU): Over boost failure

The turbocharger boost pressure level has exceeded the maximum allowable warning limit, indicating an over boost deviation at P2 too high in the Pressure charger regulator.

• MAXXUM T4E
• Case IH 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Case IH 230 Series Axial-Flow Combines (7230, 8230, 9230)
• Case IH Steiger
• Case IH Magnum
• Case IH T9

1. 1

   Emergency Re-start Check: If the machine experiences full power loss due to this code, command the engine to low idle. You can use the emergency re-start feature to gain 30 seconds of operation without power loss to safely move the machine.

2. 2

   Hose and Connector Inspection: Check the boost hoses and connectors for faults, blockages, or physical damage.

3. 3

   Sensor Voltage Verification: Check the boost pressure sensor voltage. Related codes (like 122 and 123) indicate if the sensor voltage is too high or too low, which can cause false over boost readings.

4. 4

   Regulator Monitoring: Monitor the turbocharger pressure charger regulator (wastegate) to see if it is mechanically binding or failing to vent excess pressure.

1. 1

   Safely park the machine.

   If the engine has derated, use the 30-second emergency restart function to move the equipment to a safe repair location.

2. 2

   Inspect all boost hoses and connectors.

   Inspect hoses leading to and from the turbocharger and intake manifold. Reconnect or replace any damaged hoses.

3. 3

   Test the boost pressure sensor.

   Test the boost pressure sensor and its wiring harness for shorts or voltage irregularities.

4. 4

   Inspect the turbocharger pressure charger regulator (wastegate actuator).

   If there is an over boost deviation at P2, the regulator may be stuck closed.

5. 5

   Replace faulty components.

   Replace the faulty boost pressure sensor, damaged hoses, or the turbocharger regulator assembly as dictated by the inspection.

6. 6

   Clear the ECU fault codes.

   Clear the ECU fault codes using an Electronic Service Tool (EASY Tool) and run the engine to verify the boost pressure remains within normal limits.