Case IH 3457 (DTC 1374) - ECU – Engine Control Module (ECM / Engine ECU): Intake manifold temperature sensor voltage is higher than expected.

The Engine Control Module (ECM) is receiving a voltage signal from the intake manifold temperature sensor that exceeds the normal operating parameters. This typically indicates an open circuit, a disconnected sensor, or a short circuit to a high-voltage source in the sensor's wiring harness. It can also be caused by an internal failure of the sensor itself.

• MAXXUM T4E
• 240 Series Axial-Flow Combines
• Magnum Series (MX180, MX220, MX240, MX255, MX270, MX285)
• TG Series (TG210, TG255, TG285)
• Steiger 4WD Tractors (STX275, STX325)
• FLX Floaters (FLX3010, FLX3510, FLX4010, FLX4510)
• SPX Sprayers
• CPX Cotton Pickers (CPX610, CPX620)
• Case CE CX Series Excavators (CX210, CX240, CX290, CX330)

1. 1

   Visual Inspection: Locate the intake manifold temperature sensor on the engine. Inspect the electrical plug and connector for dirt, corrosion, or pushed-out pins.

2. 2

   Wiring Harness Check: Trace the wiring harness from the sensor back to the Engine ECU. Look for chafed wires, pinched lines, or melted insulation that could cause a short to a high-voltage source or an open circuit.

3. 3

   Voltage/Resistance Testing: Use a multimeter to verify the reference voltage at the connector. Test the sensor's internal resistance to determine if the sensor itself has failed open.

1. 1

   Prepare machine

   Ensure the machine is turned off, the key is removed, and the engine has cooled down.

2. 2

   Gain access to sensor

   Locate the intake manifold temperature sensor on the side of the engine. To gain clearance, you may need to remove the left and right fan shields by removing their retaining bolts and pulling the shields out.

3. 3

   Remove obstructing plumbing

   If the turbocharger plumbing blocks access, loosen the clamps and remove the air cleaner outlet tube at the turbocharger elbow.

4. 4

   Disconnect sensor

   Disconnect the electrical plug for the intake manifold temperature sensor.

5. 5

   Remove retainers

   Remove any harness and hose retainers on the side of the engine that restrict access to the sensor.

6. 6

   Remove faulty sensor

   Unthread the faulty intake manifold temperature sensor from the manifold.

7. 7

   Install new sensor

   Install the new sensor, ensuring the O-ring (11.3mm ID x 2.2mm thickness) is properly seated to prevent boost leaks.

8. 8

   Reassemble components

   Reinstall any removed intake piping, fan shields, and harness retainers.

9. 9

   Reconnect sensor

   Reconnect the electrical plug to the new sensor.

10. 10

    Clear fault codes

    Turn on the machine and clear the fault codes using the diagnostic display or a service tool.