Spark Plug Replacement

What is a spark plug?

Spark plugs are a crucial part of the vehicle’s ignition system. They provide the spark that ignites the air-fuel mixture inside the engine, creating the chain-reaction that generates the engine’s power.

How does the spark plug work?

The spark plug turns high voltage electricity from the ignition coil into a strong spark inside the engine. This ignites the air-fuel mixture, creating power.

Failing spark plugs can cause the engine to run rough and misfire, which can trigger the Check Engine Light. Continuing to drive under these conditions can damage the catalytic converter.

What are the symptoms related to a bad spark plug?

When spark plugs fail, the engine will struggle. The check engine light will come on, and it may appear either solid or flashing. The driver would likely notice one or more of the following: engine vibrations, rough idling, poor gas mileage, excessive cranking time needed to start the engine, and power loss or surging. In extreme circumstances, the engine may stall or fail to start.

Toyota Sienna Spark Plug Replacement Cost by Year

The average cost for a Toyota Sienna Spark Plug Replacement is between $440 and $682 but can vary from car to car.

Disclaimer

Materials Included Under License from Toyota Motor Sales, U.S.A., Inc. License Agreement TMS1008. All information contained in any materials obtained about Toyota, Lexus, and Scion vehicles is based on the latest product information available at the time of publication, is provided “as is” without warranty of any kind, and is intended for service providers and other interested parties in Canada, Mexico, and the United States of America, including Guam, Puerto Rico, and the U.S. Virgin Islands. Specifications and procedures are subject to change without notice. This information is provided expressly for the purpose of use by professional automobile technicians who have special techniques and certifications. Repair or service by non-specialized or uncertified technicians using only this information, or without proper equipment or tools, may cause severe injury to the individual or other individuals and could possibly cause damage to the vehicle. Certain procedures or content elements may make reference to Toyota Warranty policy or practice – these policies or practices are only applicable to Toyota, Lexus, or Scion dealers.

Estimates last updated June 18, 2026

Toyota Sienna Spark Plug Replacement Cost

The average cost for a Toyota Sienna Spark Plug Replacement is between $440 and $682.

Labor costs are estimated between $387 and $568 while parts are priced between $53 and $114.
This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.
For a more accurate estimate based on your location, use our Fair Price Estimator below.

Spark Plug Replacement

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What is a spark plug?

How does the spark plug work?

The spark plug turns high voltage electricity from the ignition coil into a strong spark inside the engine. This ignites the air-fuel mixture, creating power.

Failing spark plugs can cause the engine to run rough and misfire, which can trigger the Check Engine Light. Continuing to drive under these conditions can damage the catalytic converter.

What are the symptoms related to a bad spark plug?

Can I drive with a spark plug problem?

The car will run with a spark plug problem, but it's not wise to keep driving it this way. If a spark plug isn't working, unburned fuel from the engine will get into the exhaust at a higher rate, causing problems for the catalytic converter. If the converter gets ruined by this unburned fuel, it will lead to a costly repair.

How are spark plug issues diagnosed?

If the spark plugs are suspected, they're checked for proper connection with the ignition coil. If that's OK, the plugs must be removed, and the spark plug gap must be checked. If the gap is too small because of corrosion, or too large because or deterioration, they will be replaced. If the spark plug is in good condition, a tester is used to find whether the spark plug is able to produce spark.

How is a spark plug replaced?

On newer vehicles, spark plug replacement involves removing the engine cover, ignition coil harness and ignition coils, and then finally the spark plugs. For most older vehicles, removing the spark plug wires and spark plugs is all that's required. Once the spark plugs are removed, the gap on the new spark plug is set, and the plug is installed using an anti-seize compound and proper torque. Prior to reinstalling the spark plug wire or ignition coil, dielectric grease is applied to the spark plug terminal to promote the transfer of electricity.