Cooling fan not working Toyota Corolla E170

Cooling Fan Not Working on Toyota Corolla E170 (2013-2019)

Tools Required:

• Digital Multimeter (DMM)
• OBD-II scanner
• Test light
• Relay puller
• Wiring diagram for the cooling fan circuit

Step 1: Visual Inspection

1. Inspect the Cooling Fan: Check for physical damage or obstructions around the cooling fan. Ensure that the fan blades are intact and can spin freely.
2. Check the Fuse: Locate the cooling fan fuse in the fuse box under the hood. Refer to the fuse box cover for the exact location. Use a test light to verify that the fuse is not blown.
3. Inspect Wiring and Connections: Check for any damaged wires, loose connections, or corrosion on the cooling fan connectors and relay socket.

Step 2: Check for Trouble Codes

1. Connect an OBD-II Scanner: Plug in the scanner to the OBD-II port and check for any stored trouble codes that might indicate a problem with the cooling system or engine temperature sensor.
2. Review the Codes: Look specifically for codes related to the cooling fan circuit or engine temperature sensor (e.g., P0480, P0481).

Step 3: Test the Cooling Fan Relay

1. Locate the Relay: Find the cooling fan relay in the under-hood fuse/relay box.
2. Swap Relays: If there is another relay with the same part number, swap them to see if the fan starts working. If it does, replace the faulty relay.
3. Test the Relay: Use a multimeter to check for continuity between the relay terminals according to the wiring diagram. Apply 12V to the control side of the relay and check if it closes the circuit.

Step 4: Test the Fan Motor

1. Direct Power Test: Disconnect the fan connector and apply 12V directly to the fan motor. If the fan operates, the motor is functional.
2. Check Resistance: Use a multimeter to measure the resistance of the fan motor windings. Compare the reading to the manufacturer's specifications.

Step 5: Check the Engine Coolant Temperature (ECT) Sensor

1. Locate the ECT Sensor: Usually found near the thermostat housing.
2. Test the Sensor: Use a multimeter to check the resistance of the ECT sensor. Compare to the specifications for the current temperature.
3. Replace if Faulty: If the resistance is outside the specified range, replace the ECT sensor.

Repair Instructions:

Fixing Wiring Issues

1. Repair or Replace Damaged Wires: If any wiring issues are found, repair using solder and heat shrink tubing or replace the wire harness section as necessary.

Replacing the Cooling Fan Relay

1. Purchase a New Relay: Obtain a replacement relay that matches the original specifications.
2. Install the New Relay: Insert the new relay into the corresponding socket in the fuse/relay box.

Replacing the Cooling Fan Motor

1. Remove the Fan Shroud: Disconnect the fan motor connector and unbolt the fan shroud assembly from the radiator.
2. Replace the Motor: Install the new fan motor and fan blades if necessary, and reassemble the fan shroud.
3. Reconnect and Test: Reconnect all connectors and test the fan operation by running the engine to operating temperature.

Conclusion:

After completing these diagnostic and repair steps, the cooling fan on your Toyota Corolla E170 should function properly. If the issue persists, further investigation into the ECM or a more detailed inspection of the wiring harness may be necessary.