Why Is Your Check Engine Light On And How Much To Fix It?

Why Is Your Check Engine Light On And How Much To Fix It?
Photo credit: virgmos/Shutterstock.com.

If one thing in life is certain, it's that at some point your check engine light will come on. Probably at an inopportune time, too. But whenever it is, we caution you not to ignore it. Especially in the age of Covid. According to CarMD, a provider of automotive diagnostic and business solutions, 2020 led to financial challenges for many, which means some people held on to older vehicles longer than ever before. CarMD says these changes impacted the age of vehicles and the types of repairs needed.

Top 5 Check Engine Light Causes

So what are the top five causes of check engine lights and how much will they set you back? There are no big surprises in the list, which pretty much mimics that of 2020. The 2021 CarMD Vehicle Health Index lists the top five most common check engine light-related repairs in 2020 along with the average cost to make that repair, including parts and labor.

  1. Replace catalytic converter(s) with new OE catalytic converter(s) - $1,383
  2. Replace oxygen sensor(s) - $243
  3. Replace ignition coil(s) and spark plug(s) - $389
  4. Replace mass air flow sensor - $336
  5. Tighten or replace fuel cap - $25

CarMD says each of these issues will keep a vehicle from passing its state emissions test and negatively impact fuel economy if ignored.

"We want vehicle owners to utilize the information provided by CarMD to become informed about the importance of being attentive to scheduled maintenance and addressing check engine light issues in a timely manner, which can positively impact fuel economy, extend vehicle life, reduce the likelihood of future repairs and make it easier to pass a smog test," said David Rich, CarMD technical director. "We don't want people to panic when they hear that catalytic converters are the most common repair. It's important to remember that while catalytic converters are costly, they don't typically fail unless maintenance and other repairs like as a faulty oxygen sensor or ignition coil are ignored, or a vehicle has high mileage."

As we've reported recently here at CarProUSA, there's been a dramatic increase of catalytic converter thefts during the pandemic, according to the National Insurance Crime Bureau. Thieves are after the precious metals they're made of such as rhodium that can be sold to metal recyclers.

  • In 2019, an average of 282 catalytic converters were stolen every month
  • In 2020 the average had risen to 1,203.

Rich adds that the uptick in catalytic converter replacements and need for these parts can be partially explained by the increase in the average vehicle age to an all-time high of 11.9 years in 2020. As people keep their cars and trucks longer, the automotive aftermarket will need to adjust related parts supply forecasts accordingly.

Here are some other 2021 CarMD Vehicle Health Index findings according to its press release:

In 2020 car repair costs were down 1.6% overall at an average of $378.77. Labor costs were down 2.8% yearover-year from 2019 to 2020, and parts costs were down about 1%. Many factors likely played a role in this decrease, including the economy, competition among repair shops and an increase in DIY automotive repairs during the pandemic. CarMD anticipates an increase in parts costs next year given the material shortage resulting from shutdown-related supply chain issues.

New this year CarMD broke down the Index by vehicle model year. Model year 2007 vehicles were most likely to need check engine light repairs, accounting for 9.9% of problems seen by CarMD across all models last year. As many as 29% of inspected model year 2007 vehicles had a check engine light on. A vehicle will not pass its emissions test, required by most states to register a vehicle, if the check engine light is on. The most commonly diagnosed repair on a 2007 vehicle was 'replace ignition coil(s) and spark plug(s).' Not surprisingly, vehicles that are less than 3 years old didn't experience many check engine light issues, accounting for fewer than 1% of needed repairs reported to CarMD.

CarMD's data reports an increase in mass air flow sensors (MAF sensors) needing replacement, while fuel cap issues continue to trend down. MAF sensors moved from the no. 5 to the no. 4 most common repair. Gas cap issues dropped again moving from the no. 4 to no. 5 most frequent repair. This and other national and regional trend data in the full report can inform automotive parts suppliers, aftermarket retail buyers and other industry experts as they extrapolate year-over-year and trends related to vehicle diagnostic data and related parts failures.