my Toyota Corolla E140 (2006-2013) check engine light is on what could it be

Solution

1. Preparation

• Gather tools and parts required for repairs.
• Disconnect the negative battery terminal to ensure safety.

2. Retrieve and Analyze Codes

• Connect the OBD-II scanner to the vehicle's diagnostic port.
• Turn on the ignition (do not start the engine) and retrieve error codes.
• Note down the specific codes and refer to a repair manual for diagnostic information.

3. Address Specific Codes

• Based on the retrieved error codes:
  • For Oxygen Sensor Issues:
    1. Locate the faulty oxygen sensor (typically in the exhaust system).
    2. Disconnect the sensor's electrical connector.
    3. Remove the sensor using an oxygen sensor socket.
    4. Install the new sensor, tightening it to the manufacturer’s specifications (usually 30-35 lb-ft).
  • For Misfire Codes:
    1. Inspect and replace faulty spark plugs (torque to manufacturer specifications).
    2. Check and replace any faulty ignition coils.
  • For Fuel System Issues:
    1. Check fuel lines and connections for leaks.
    2. Test fuel pressure using a fuel pressure gauge; replace the fuel pump if necessary.

4. Clear Codes and Reassemble

• After repairs, reconnect all connectors.
• Reconnect the negative battery terminal.
• Clear the trouble codes using the OBD-II scanner.