Toyota Highlander Bad Ignition Coils Symptoms and Solutions

As the famous saying goes, “A car is a lot like a spouse, it requires constant attention and maintenance.” This holds true for the Toyota Highlander, a popular mid-size SUV known for its reliability and durability.

However, even the most well-maintained vehicles can experience problems, and one of the most common issues that Toyota Highlander owners face is faulty ignition coils.

Since the ignition coil plays a critical role in starting and powering a vehicle, you should be aware of the symptoms and solutions of bad ignition coils.

Symptoms of bad ignition coils in a Toyota Highlander include misfiring, shaking, and decreased engine power. Solutions for this issue include replacing the bad coil(s) and ensuring that the spark plugs are in good condition.

In this guide, we will explore the Toyota Highlander bad ignition coils symptoms and solutions to ensure your driving smoothly. 

Role of Ignition Coils on Toyota Highlander

The ignition coils in a Toyota Highlander are responsible for converting the low voltage from the battery into the high voltage necessary to create a spark in the spark plugs. The spark plugs ignite the air-fuel mixture in the engine, which powers the vehicle.

Each cylinder in the engine has its ignition coil, and they work together to provide the spark necessary for combustion. A faulty ignition coil can cause engine misfires, rough idling, and decreased fuel efficiency.

Symptoms of Bad Ignition Coils in a Toyota Highlander

If one or more ignition coils fail, it can lead to a range of problems, including engine misfires, decreased fuel economy, and even stalling. Here are some common symptoms of bad ignition coils in a Toyota Highlander.

1. Check Engine Light

A malfunctioning ignition coil can cause the engine control module to detect a problem and trigger the Check Engine light on the dashboard. This warning light indicates a problem with the engine that needs to be addressed.

2. Engine Misfires

If one or more ignition coils fail, it can cause the engine misfires. A misfire occurs when the fuel in the combustion chamber is not ignited correctly, leading to a rough idle, hesitation, or reduced performance. Misfires can cause damage to the engine over time, so it’s essential to address this problem promptly.

3. Decreased Fuel Economy

A bad ignition coil can cause the engine to run less efficiently, leading to decreased fuel economy. If you notice that your Toyota Highlander is using more fuel than usual or that you need to refuel more often, there may be an issue with one or more of the ignition coils.

4. Stalling

If the ignition coils are not working correctly, they may not produce enough voltage to ignite the fuel in the combustion chamber, causing the engine to stall. Stalling can occur at idle or while driving and is a potentially dangerous situation that needs to be addressed promptly.

5. Difficulty Starting

A bad ignition coil can cause difficulty starting the engine, especially in cold weather. If you notice that it takes longer to start your Toyota Highlander or that it’s harder to start when the engine is cold, there may be an issue with one or more ignition coils.

Causes of Bad Ignition Coils in a Toyota Highlander

The ignition coils in a Toyota Highlander play a crucial role in the engine’s performance, and a malfunctioning coil can cause a variety of issues. Here are some of the most common causes of bad ignition coils in a Toyota Highlander.

  • Age and Wear: Ignition coils have a limited lifespan and can wear out over time. The high heat and electrical currents they are exposed to can cause damage to the coils and lead to failure.
  • Overheating: The ignition coils can overheat due to a variety of factors, such as a malfunctioning cooling system, clogged air filter, or engine running at high RPM for an extended period. Overheating can damage the coils and cause them to fail.
  • Contamination: Dirt and debris can get into the engine bay and affect the performance of the ignition coils. Oil and other fluids can also leak into the engine bay, damaging the coils and causing them to malfunction.
  • Voltage Surges: Voltage surges can occur due to issues with the alternator, battery, or other electrical components. These surges can damage the ignition coils and cause them to fail.
  • Corrosion: Corrosion on the ignition coil terminals or connectors can cause resistance in the electrical circuit, leading to poor performance and eventual failure.

Solutions for Bad Ignition Coils in a Toyota Highlander

If you are experiencing issues with the ignition coils in your Toyota Highlander, there are a few solutions that you can try to get your engine running smoothly again. Here are some of the most effective solutions for bad ignition coils.

Solution 1: Replace the Ignition Coils

If your Toyota Highlander is experiencing issues with the ignition coils, the most effective solution is to replace them. A new set of coils will ensure that your engine receives the proper voltage and help prevent misfires and other issues. It is important to use high-quality replacement coils designed for your specific vehicle to ensure optimal performance.

Solution 2: Check and Replace Spark Plugs

The spark plugs in your Toyota Highlander work in conjunction with the ignition coils to ignite the air-fuel mixture in the engine. If your coils are malfunctioning, your spark plugs may be also worn out or damaged. So, check your spark plugs and replace them if necessary.

Solution 3: Clean or Replace the Air Filter

A clogged or dirty air filter can cause issues with the ignition coils and other engine components. If the air filter is dirty, it can restrict airflow to the engine, causing it to run rich or lean, damaging the ignition coils. In that case, you have to clean or replace the air filter to ensure proper airflow to the engine.

Solution 4: Repair or Replace the Alternator

The alternator in your Toyota Highlander is responsible for charging the battery and providing power to the electrical components, including the ignition coils. If the alternator is malfunctioning, it can cause voltage surges that can damage the coils. Repair or replace the alternator to prevent further damage to the ignition coils.

Solution 5: Clean or Replace the Mass Airflow Sensor

The mass airflow sensor in your Toyota Highlander measures the amount of air entering the engine and sends this information to the engine control module. If the mass airflow sensor is dirty or malfunctioning, it can cause the engine to run lean, which can damage the ignition coils. So, clean or replace the mass airflow sensor to ensure accurate readings and proper engine performance.

Cost to Fix Bad Ignition Coils in a Toyota Highlander From Professional

The cost to fix bad ignition coils in a Toyota Highlander can vary depending on the severity of the problem and the type of repair needed. In general, the cost can range from $200 to $800 or more, including parts and labor.

The price of replacement ignition coils can vary based on the make and model of your Highlander, with OEM parts generally costing more than aftermarket options.

Labor costs can also vary based on the mechanic’s experience and location. It’s best to consult with a professional mechanic for an accurate estimate of the cost of fixing bad ignition coils in your Toyota Highlander.

Conclusion

Toyota Highlander is a reliable car and can last for years, however, it is important to be aware of the symptoms and solutions for bad ignition coils. Hopefully, you already figure out Toyota Highlander bad ignition coils symptoms and solutions through this guide above.

In general, ignition coil problems can cause various issues, such as engine misfires, reduced performance, and decreased fuel economy. The most common solutions for bad ignition coils are replacing the coils and spark plugs, replacing the ignition wires, and cleaning the coils.

Additionally, regular maintenance and inspection of the ignition coils may help to prevent any serious problems. Taking the necessary steps to address ignition coil issues can help prevent the need for costly repairs and ensure the car is running at its best.

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