Each year, CarMD conducts a national auto repair study to determine average repair costs, top repairs my model year and even the Most Common “Check Engine” Light Repairs. While we may find it way more fun to dig into the data than many of you, here is information we think will be helpful for you.
If you have a Check Engine light triggered by a faulty oxygen sensor, you’re not alone. This repair topped the list in this year’s study and last year’s, too. The oxygen sensor monitors the amount of raw fuel in the exhaust stream before and after it reaches the catalytic converter. It then signals your car’s onboard computer to increase or decrease the amount of fuel being sent to the engine. Most cars today have at least two oxygen sensors; many have four. If a sensor is beginning to fail, it can allow too much fuel to go into the catalytic converter, which can damage reduce the converter’s lifespan. Converters are expensive (see #2 on the list), so if your mechanic tells you the oxygen sensor has failed, replace it right away.
The average cost to replace an oxygen sensor in the Midwest: $240.
#2) Replace Catalytic Converter with New Original Equipment Converter
The catalytic converter’s job is to clean up your car’s exhaust before it’s pushed out into the atmosphere. As the converter ages, it becomes less and less effective until it can no longer adequately reduce the vehicle’s tailpipe emissions. This will eventually trigger the Check Engine light and a major repair bill. There’s not much you can do to head off a repair like this, except replace any oxygen sensor that’s nearing the end of its useful life.
The average cost to replace a catalytic converter in the Midwest: $1,135. This assumes the converter is being replaced by an OEM brand, not an aftermarket or cheaper alternative.
#3) Replace Ignition Coil and Spark Plug
Your engine needs three things to run: fuel, air and a spark. Ignition coils and spark plugs are tasked with providing the spark that ignites the fuel and air mixture in each engine cylinder. If a coil or plug begins to fail, your car is likely to run extremely rough—as if it’s not running on all cylinders—and your Check Engine light will pop on.
Typically, if one ignition coil begins to fail, the others are not far behind. In many cases, your auto repair shop will recommend replacing the other ignition coils and spark plugs all at the same time. This is especially true if your engine is built in such a way that it takes a lot of time to access the ignition coils. Yes, you’re paying for parts now that haven’t failed yet. But if you don’t replace them now and a coil fails in the next few weeks or months, you’ll have to pay for all that labor all over again.
The average cost to replace an ignition coil and spark plug in the Midwest: $387.
#4) Tighten or Replace Fuel Cap
This is the most budget-friendly diagnosis you can hope for. A loose fuel cap or one that has a worn seal allows fuel vapors to escape into the atmosphere, which will trigger the Check Engine light. As you can guess, the repair is a simple one, either tighten or replace the fuel cap.
The average cost to replace a worn fuel cap in the Midwest: $13.
#5) Replace Thermostat
A faulty thermostat is nothing new to most of us. It’s role in our vehicle operation hasn’t changed for decades. The thermostat is still responsible for controlling the flow of coolant through the radiator and the engine, helping to dissipate some of the intense heat. If your thermostat fails and is “open” all the time, you’ll likely notice a lack of heat in the passenger compartment. If the thermostat fails and is always closed, you’ll quickly see a warning for excessive engine temperature. Pull over safely ASAP, turn off the car and call for a tow truck. Otherwise, you risk a literal meltdown in the engine, which is very costly to repair. Surprisingly, this repair jumped from the No. 10 spot on last year’s survey.
The average cost to replace a failed thermostat in the Midwest: $210.
The next time your Check Engine or Service Engine Soon light comes on, schedule an appointment with Hong Kong Auto Service. Whether your repair falls into the Top 5 or the bottom 25, we have the tool, skills and experience to repair your car quickly and accurately. We’ll have you back on the road with minimal disruption and maximum peace of mind, including a 3-year/36,000-mile warranty.