Iveco 131 – EDC: Coolant Temperature Sensor Circuit Malfunction

Fault code 0131 indicates an electrical issue within the engine coolant temperature (ECT) sensor circuit. The engine control unit (EDC) is detecting an open circuit, a short circuit, or a voltage/resistance signal that falls outside the expected operating range, which prevents the system from accurately monitoring engine temperature.

• Iveco Daily
• Iveco Stralis
• Iveco Trakker
• Iveco Eurocargo
• Iveco Tector
• FPT NEF engines
• FPT Cursor engines

1. 1

   Inspect the wiring harness and the 2-pin connector at the coolant temperature sensor for corrosion, frayed wires, or loose connections.

2. 2

   Disconnect the sensor and measure its internal resistance using a multimeter (a healthy sensor typically reads approximately 2.5 kΩ at 20°C/68°F).

3. 3

   Turn the ignition ON (engine off) and probe the harness connector to verify the EDC supplies a 5V reference voltage to one pin and a sensor ground to the other.

1. 1

   Prepare engine

   Ensure the engine is completely cool to prevent burns and system depressurization.

2. 2

   Drain coolant

   Partially drain the engine coolant from the radiator petcock until the fluid level is below the thermostat housing/sensor location to prevent spills.

3. 3

   Remove faulty sensor

   Disconnect the electrical connector from the sensor. Using a deep socket or wrench, carefully unthread the faulty coolant temperature sensor from the engine block or thermostat housing.

4. 4

   Install new sensor

   Thread the new sensor into place. Do not overtighten, as the brass threads can shear. Tighten to the OEM specified torque (usually hand-tight plus a quarter turn, or ~20 Nm depending on thread size).

5. 5

   Reassemble and refill

   Reconnect the 2-pin electrical connector. Refill the engine coolant to the proper level.

6. 6

   Bleed system and clear codes

   Reconnect the battery. Start the engine and let it idle with the heater on to bleed any trapped air from the cooling system. Use an OBD/diagnostic scanner to clear the 0131 fault code from the EDC memory. Verify that the dashboard temperature gauge reads correctly as the engine warms up.