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What are the signs of a failing ignition coil in a 2020 Highlander? - Toyota Highlander
Home/Cars/Toyota/Highlander/Fourth Generation (2020-present)/What are the signs of a failing ignition coil in a 2020 Highlander?

What are the signs of a failing ignition coil in a 2020 Highlander?

Toyota Highlander Fourth Generation (2020-present)

Error Codes
1-2 hours
Time
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
4 min read
642 words

Problem Statement

Learn about the symptoms of a failing ignition coil in a 2020 Toyota Highlander and how to diagnose and replace it.

Affected Component
ignition coil
Estimated Time
1-2 hours

Symptoms

  • •Engine Misfire
  • •Decreased Fuel Efficiency
  • •Check Engine Light
  • •Hard Starting or No Start
  • •Rough Idle
  • •Loss of Power

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5

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
  • •Digital multimeter
  • •Basic hand tools (sockets, wrenches, etc.)
  • •Torque wrench
  • •Safety gloves and goggles

Additional Information

Affected Component
ignition coil
Estimated Time
1-2 hours
Difficulty
medium
Severity
medium
Tools Required
5 items

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Signs of a Failing Ignition Coil in a 2020 Toyota Highlander

A failing ignition coil can lead to various performance issues in your vehicle. Here are some common symptoms you may notice in a 2020 Toyota Highlander:

  1. Engine Misfire: You may experience a rough idle or a noticeable misfire, especially during acceleration. This can feel like a hiccup or stutter in the engine's power delivery.

  2. Decreased Fuel Efficiency: A failing ignition coil can cause the engine to run inefficiently, leading to reduced fuel economy.

  3. Check Engine Light: The check engine light may illuminate on your dashboard, often accompanied by a trouble code related to the ignition system.

  4. Hard Starting or No Start: The vehicle may become difficult to start, or it may not start at all.

  5. Rough Idle: The engine may idle roughly, indicating that it is not running smoothly.

  6. Loss of Power: You may notice a lack of acceleration or power, especially when going uphill or under load.

Tools Required
  • OBD-II scanner
  • Digital multimeter
  • Basic hand tools (sockets, wrenches, etc.)
  • Torque wrench
  • Safety gloves and goggles
Repair Instructions

If you confirm that the ignition coil is faulty and needs replacement, follow these steps:

  1. Safety Precautions:

    • Ensure the vehicle is parked on a flat surface, the engine is off, and the keys are removed from the ignition.

  2. Disconnect the Battery:

    • Disconnect the negative terminal of the battery to prevent any electrical shorts.

  3. Access the Ignition Coil:

    • Depending on the cylinder location, you may need to remove engine covers or components to access the ignition coils.

  4. Remove the Ignition Coil:

    • Disconnect the electrical connector from the ignition coil.
    • Remove the bolts or screws securing the ignition coil in place (usually a single bolt).
    • Carefully pull the coil out of the spark plug well.

  5. Install New Ignition Coil:

    • Apply a small amount of dielectric grease to the boot of the new ignition coil.
    • Insert the new coil into the spark plug well and secure it using the original bolts/screws.
    • Reconnect the electrical connector.

  6. Reconnect the Battery:

    • Reconnect the negative terminal of the battery.

  7. Test the Vehicle:

    • Start the engine and check for proper operation. Monitor for any warning lights and ensure the engine runs smoothly.

  8. Clear Trouble Codes:

    • If you used an OBD-II scanner, clear any stored trouble codes after confirming the engine runs properly.
Conclusion

If the symptoms persist after replacing the ignition coil, further diagnostic work may be necessary to check for other ignition system components, such as spark plugs or the ignition control module. Always refer to the vehicle's service manual for specific instructions and specifications.