Iveco 02F8 – Engine Control Unit (ECU): Incorrect signal in the exhaust gas temperature sensor circuit

The engine control module is receiving an implausible voltage or resistance reading from the Exhaust Gas Temperature Sensor (EGTS). This typically points to an open circuit, a short circuit to ground, a damaged wiring harness, or a complete failure of the sensor's internal thermistor element.

• Iveco Stralis
• Iveco Trakker
• Iveco Eurocargo
• Iveco Daily
• Iveco Citelis
• Iveco Crealis
• Iveco Crossway

1. 1

   Scan for associated codes related to the DPF, SCR, or turbocharger to rule out broader exhaust system issues

2. 2

   Visually inspect the EGTS wiring harness and connectors for melted wires, chafing, corrosion, or loose pins

3. 3

   Use a multimeter to check for a short to ground or an open circuit in the sensor wiring leading back to the EDC

4. 4

   Measure the resistance of the sensor across its terminals and compare it against the specific Iveco engine manual's specifications for the ambient temperature

1. 1

   Preparation

   Turn off the ignition, disconnect the vehicle's battery, and ensure the exhaust system has completely cooled down to prevent severe burns.

2. 2

   Locate and Disconnect

   Locate the faulty exhaust gas temperature sensor on the exhaust pipe or manifold. Disconnect the 2-pin electrical connector.

3. 3

   Removal

   Using a suitable wrench (often 14mm), carefully unscrew the sensor from the exhaust pipe. If the sensor is seized due to heat cycling, apply penetrating oil to the threads and allow it to soak before attempting removal to avoid stripping the exhaust bung threads.

4. 4

   Preparation of New Sensor

   If the new OEM sensor does not come with pre-applied anti-seize compound, apply a small amount of high-temperature anti-seize to the threads. Caution: Do not get any compound on the sensor probe tip, as this will contaminate it and cause immediate failure.

5. 5

   Installation

   Thread the new sensor into the exhaust bung by hand to prevent cross-threading, then tighten it to the manufacturer's specified torque.

6. 6

   Reconnection

   Reconnect the electrical connector. Ensure the wiring cable is routed correctly and secured away from direct contact with hot exhaust components.

7. 7

   Clear Codes

   Reconnect the battery. Connect a diagnostic scanner to the OBD port, clear the 02F8 fault code, and perform a test drive to ensure the engine control unit registers the correct temperature parameters and the code does not return.