how to fix my Toyota Highlander’s engine light when it’s on

Solution

1. Preparation

• Gather tools: OBD-II scanner, socket set, torque wrench, multimeter, basic hand tools.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Addressing Specific Codes

• Based on the error codes retrieved, address each issue:

  • For a misfire code (e.g., P0300-P0306):

    1. Inspect and replace spark plugs if worn or fouled.
    2. Check ignition coils for proper operation and replace if faulty.
    3. Test fuel injectors for clogs or malfunction and clean or replace as necessary.

  • For oxygen sensor codes (e.g., P0131-P0167):

    1. Locate the faulty oxygen sensor based on the code.
    2. Disconnect the sensor's electrical connector.
    3. Remove the sensor using an oxygen sensor socket; apply anti-seize compound on the threads of the new sensor.
    4. Install the new sensor and reconnect the electrical connector.

  • For catalytic converter codes (e.g., P0420-P0430):

    1. Inspect the catalytic converter for physical damage or blockages.
    2. If damaged, replace with an OEM or quality aftermarket catalytic converter.

3. Reconnecting Battery

1. Once repairs are completed, reconnect the negative battery terminal.
2. Ensure all connections are secure.