Thornhill Auto Repair

Service is our business

Serving the thornhill area since 1972

thornhill Check Engine Light Diagnostics

Here are the five most common reasons your "check engine" light might come on

Faulty Oxygen Sensor

The sensor measures the amount of unburned oxygen in the exhaust and tells the car's computer how much fuel is in the tank. If a faulty one is not repaired, the car's gas mileage could drop, since the sensor is sending incorrect information to the car.

Loose or missing Gas Cap

Technicians will often tighten the gas cap for free, or replace it for a few dollars. If it's not replaced, gas will evaporate from the car and decrease its gas mileage.

Faulty Catalytic Converter

The catalytic converter uses a catalyst - most often a precious metal such as platinum - to convert harmful gases left over from combustion to less harmful emissions. Catalytic converters generally won't fail unless a related part, such as a spark plug, malfunctions, so it's wise to keep up with the car's maintenance schedule.

Failed Mass Air Flow Sensor

This sensor measures the amount of air supplied to the engine, which determines how much fuel should be delivered. When it malfunctions, it can result in a loss of power to the car, surges during acceleration and a decrease in fuel economy.

Misfiring Spark Plugs

Spark plugs are small but essential, since power the engine by igniting the compressed fuel in an internal combustion engine. Misfiring spark plugs can affect engine power and fuel economy and can also damage the catalytic converter. We are the experts in Thornhill check engine light.