Iveco 133 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Temperature Sensor Circuit Malfunction of the intake air

The Engine Control Unit is receiving an implausible value from the Intake Air Temperature (IAT) sensor. The underlying condition is typically an electrical fault, specifically a short circuit to positive (+), a short circuit to ground/earth, or an open circuit.

• Iveco Daily
• Iveco Stralis
• Iveco Trakker
• Iveco Eurocargo

1. 1

   Visual Inspection: Inspect the wiring harness leading to the IAT sensor (often integrated into the MAP/Boost pressure sensor) for chafed wires, broken connections, or corrosion inside the connector plug.

2. 2

   Voltage and Ground Check: Verify that the sensor connector is receiving the correct reference voltage (typically 5V) and has a solid ground from the EDC module.

3. 3

   Continuity Test: Perform a continuity check of the wiring harness between the sensor connector and the EDC control module pins to rule out an open circuit.

4. 4

   Sensor Resistance Test: Measure the resistance across the sensor's terminals using a multimeter and compare to ambient temperature specifications. Infinite or zero resistance indicates internal failure.

5. 5

   Live Data Verification: Use an OBD/EDC diagnostic scan tool to view live intake air temperature data. Extreme default values (-40°C or +130°C) confirm a hard circuit fault.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the Intake Air Temperature sensor. On many Iveco engines, this is a combined 'Air Pressure and Temperature Sensor' (T-MAP) located on the intake manifold or the boost/charge air pipe.

3. 3

   Remove the Faulty Sensor

   Depress the locking tab on the electrical connector and unplug it. Remove the mounting screw(s) holding the sensor in place and carefully pull the sensor out of the manifold.

4. 4

   Clean the Port

   Wipe away any carbon buildup or oil residue from the sensor mounting port on the intake manifold to ensure the new sensor seals correctly.

5. 5

   Install the New Sensor

   Insert the new sensor (ensure the O-ring is seated properly) and tighten the mounting fastener to the manufacturer's specified torque.

6. 6

   Reconnect Wiring

   Plug the electrical connector back in, ensuring it clicks and locks securely.

7. 7

   Clear Codes

   Reconnect the battery, turn the ignition on, and use a diagnostic scan tool to clear the 0133 / P0113 fault codes from the EDC memory.

8. 8

   Test Drive

   Start the engine and verify that the EDC warning light turns off. Monitor live data on the scan tool to ensure the intake air temperature reading is now plausible and fluctuates normally with engine operation.