Toyota Highlander Third Generation (2014-2019) check engine light keeps coming on how to fix

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

3 min read

478 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix the check engine light issue in Toyota Highlander 2014-2019. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Allow engine to cool completely before performing any repairs.

Symptoms

•Check engine light illuminated
•Poor fuel economy
•Engine stalling or misfiring
•Rough idle
•Loss of power during acceleration
•Increased emissions

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific issues.
2
Inspect gas cap for damage or looseness, as this can trigger the CEL.
3
Check engine oil and coolant levels to ensure they are within normal ranges.
4
Examine air filter for clogs or excessive dirt that could affect air intake.
5
Inspect spark plugs and ignition coils for wear or failure.
6
Conduct a visual inspection of vacuum hoses for leaks or damage.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Socket set
•Torque wrench
•Screwdriver set
•Pliers
•Oxygen sensor socket

Parts Required

•Spark plugs
•Oxygen sensors
•Vacuum hoses

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific issues.
2
Inspect gas cap for damage or looseness, as this can trigger the CEL.
3
Check engine oil and coolant levels to ensure they are within normal ranges.
4
Examine air filter for clogs or excessive dirt that could affect air intake.
5
Inspect spark plugs and ignition coils for wear or failure.
6
Conduct a visual inspection of vacuum hoses for leaks or damage.

Solution

1. Preparation

Gather tools and parts needed.
Ensure the vehicle is parked on a level surface and the engine is cool.
Disconnect the negative battery terminal to reset the ECU.

2. Replace Faulty Components

Spark Plugs:
- Remove the ignition coil cover (if applicable).
- Disconnect the ignition coil connectors and remove the ignition coils.
- Use a spark plug socket to remove old spark plugs and replace with new ones, ensuring proper torque (~13-15 ft-lbs).
Oxygen Sensors (if indicated by codes):
- Locate the faulty oxygen sensor (upstream or downstream).
- Disconnect the sensor connector and use an oxygen sensor socket to remove it.
- Install a new sensor, ensuring the connector is securely attached.

3. Repair or Replace Vacuum Hoses

Inspect all vacuum hoses visually for signs of wear or cracks.
Use pliers to remove any damaged hoses and replace with new ones.
Ensure all connections are tight and secure.

4. Reassemble and Reset

Reconnect the negative battery terminal.
Start the engine and allow it to reach operating temperature.
Monitor the engine for any abnormal sounds or behaviors.