Iveco 145 – Engine Control Unit (ECU) / EDC (Electronic Diesel Control): Fault of control circuit of the fan relay No. 1

An electrical fault (such as an open circuit, a short to ground, or a short to battery voltage) in the wiring or the coil of the primary cooling fan relay, preventing the engine control module from commanding the cooling fan to turn on.

• Iveco Daily
• Iveco Stralis
• Iveco Trakker

1. 1

   Perform an active actuation test using a diagnostic scanner to listen for the relay clicking and clutch engaging

2. 2

   Check the main engine compartment fuse box for blown cooling fan fuses (often F2 or F11)

3. 3

   Test the continuity of the fan relay coil to ensure it is not open or short-circuited

4. 4

   Check the wiring harness continuity between the EDC connector (e.g., pin A39) and the relay socket

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the negative battery terminal to prevent electrical shorts during testing.

2. 2

   Locate the Relay

   Locate the cooling fan relay 1 in the vehicle's main fuse/relay box (typically located in the engine compartment; often designated as R1 or R5).

3. 3

   Inspect the Socket

   Remove the relay and inspect the socket terminals for signs of melting, corrosion, or pushed-out pins.

4. 4

   Test/Replace the Relay

   Use a multimeter to test the resistance across the relay's control coil pins. If the coil is open (infinite resistance) or shorted, the relay is defective and must be replaced.

5. 5

   Harness Repair

   If the relay tests fine, use a multimeter to trace the control wire from the relay block back to the EDC harness. Repair any chafed insulation or broken wires causing a short/open circuit.

6. 6

   Reassembly and Clearing

   Install a known-good relay, reconnect the battery, and use your diagnostic scanner to clear the 0145 fault code.

7. 7

   Verification

   Run the engine up to operating temperature or use the scanner's active test function to verify that the fan engages at the correct temperature threshold without triggering the code.