how to change the spark plugs on my Toyota Highlander Third Generation (2014-2019)

Toyota Highlander Third Generation (2014-2019)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

549 words

Problem Statement

Learn how to change spark plugs on Toyota Highlander (2014-2019) for optimal performance. Step-by-step guide with tools and safety tips included.

Affected Component

Engine

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components.
•Ensure the engine is cool to avoid burns when working near hot engine components.

Symptoms

•Engine misfire or rough idle
•Poor acceleration or loss of power
•Decreased fuel economy
•Check engine light illuminated
•Difficulty starting the engine

Diagnostic Steps

1
Review the vehicle's maintenance history for the last spark plug replacement interval.
2
Use an OBD-II scanner to check for any related error codes.
3
Inspect the existing spark plugs for signs of wear, such as carbon buildup or electrode erosion.
4
Check the ignition coils for proper function, as faulty coils can affect spark plug performance.

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

•Socket set (including spark plug socket)
•Torque wrench
•Ratchet and extensions
•Spark plug gap tool
•Dielectric grease

Parts Required

•New spark plugs

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Diagnostic Steps

1
Review the vehicle's maintenance history for the last spark plug replacement interval.
2
Use an OBD-II scanner to check for any related error codes.
3
Inspect the existing spark plugs for signs of wear, such as carbon buildup or electrode erosion.
4
Check the ignition coils for proper function, as faulty coils can affect spark plug performance.

Solution

1. Preparation

Gather necessary tools and parts.
Tools Required:
- Socket set (including spark plug socket)
- Torque wrench
- Ratchet and extensions
- Spark plug gap tool
- Dielectric grease
Parts Required:
- New spark plugs (consult owner's manual for specifications)
Make sure the engine is cool before starting work.

2. Remove Engine Cover (if applicable)

Locate and remove any screws or bolts securing the engine cover using a socket or screwdriver.
Gently lift the cover off and set it aside.

3. Access Spark Plugs

Identify the ignition coil locations above each spark plug.
Disconnect the electrical connectors from each ignition coil by pressing the tab and pulling it off.
Remove the bolts securing the ignition coils using a socket, then carefully pull the coils out.

4. Remove Old Spark Plugs

Using a spark plug socket, carefully unscrew each spark plug from the cylinder head.
Inspect the removed spark plugs for wear and carbon build-up.

5. Install New Spark Plugs

Check the gap on the new spark plugs using a spark plug gap tool and adjust if necessary to the manufacturer's specifications.
Apply a small amount of dielectric grease to the threads of the new spark plugs.
Carefully thread the new spark plugs into the cylinder head by hand to avoid cross-threading, then tighten using a torque wrench to the manufacturer's specified torque (typically around 13-15 lb-ft).

6. Reinstall Ignition Coils

Reinsert each ignition coil onto the corresponding spark plug, ensuring it is seated properly.
Tighten the bolts to secure the ignition coils using a socket.
Reconnect the electrical connectors to each ignition coil until you hear a click.

7. Reinstall Engine Cover

Place the engine cover back on and secure it with screws or bolts.