5 most common check engine light-related repairs

With the number of challenges the year 2020 brought for people across the country, many vehicle owners were led to holding onto their older vehicle longer than expected. In doing so, this has impacted the age of vehicles and types of repairs. 

CarMD.com Corporation, a leading provider of automotive diagnostic data and business solutions, breaks down the five most common check engine light-related repairs in 2020, along with the average repair costs and other key findings in its 2021 Vehicle Health Index. The index is a year-over-year review on vehicle data related to the type and cost of repairs. 

The five most common check engine light-related repairs in 2020 and 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 

Each of these issues above will keep a vehicle from passing its state emissions test and negatively impact fuel economy if left unnoticed.

The 2021 Vehicle Health Index also found that in 2020, car repair costs were down 1.6 percent overall at an average of $378.77. Labor costs were down 2.8 percent year-over-year from 2019 to 2020, and parts costs were down about 1 percent. 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 percent of problems seen by CarMD across all models last year. As many as 29 percent 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 three years old didn't experience many check engine light issues, accounting for fewer than 1 percent 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.

To view the complete 2021 CarMD Vehicle Health Index, click here.