Vehicle Health Index2018-09-18T19:10:11+00:00

Vehicle Health Index

Vehicle Health Index

The CarMD® Vehicle Health Index™ reports on the most common check engine light-related problems, repairs and associated costs. Published annually since 2011, this Index provides year-over-year car repair data.

The check engine light comes on when a vehicle’s computer detects a problem that affects emissions or drivetrain issues. If ignored, it will hurt the environment, the car’s fuel economy and lead to more problems down the road.

Learn More
Vehicle Health Index

The CarMD® Vehicle Health Index™ reports on the most common check engine light-related problems, repairs and associated costs. Published annually since 2011, this Index provides year-over-year car repair data.

The check engine light comes on when a vehicle’s computer detects a problem that affects emissions or drivetrain issues. If ignored, it will hurt the environment, the car’s fuel economy and lead to more problems down the road.

Learn More

2018 Vehicle Health Index

Highlights – Check Engine Light Insight at a Glance

According to CarMD, during 2017 the following were the five most common check engine light-related car repairs and associated average repair costs, including parts and labor. If left unrepaired, each can negatively impact fuel economy and harm the environment.


  1. Replace oxygen sensor – $238
  2. Replace ignition coil(s) and spark plug(s) – $367
  3. Replace catalytic converter – $1,271
  4. Tighten or replace fuel cap – $26
  5. Replace evaporative emissions (EVAP) purge control valve – $147

Don’t panic when the check engine light comes on, but get it diagnosed ASAP. It can be as simple as a loose gas cap. But a flashing check engine light can indicate a more serious problem such as an engine misfire that needs immediate attention from roadside assistance.

Diagnostic trouble codes (DTCs) are 5-digit alphanumeric codes that identify the trouble area and help identify why the check engine light is on.

The 1st character is a letter that defines the main system where the problem occurred. The 2nd is a number that identifies the type of code.

The 3rd IDs the affected system, and the 4th and 5th characters define the section of the system that’s malfunctioning.

The most common DTC in 2017 was P0420, which indicates Catalyst B1 Deterioration that often signifies a faulty oxygen sensor or catalytic converter.

According to CarMD’s findings, in 2017 the oxygen sensor remained the no. 1 most common check engine light culprit, following by no.2 ignition coil and spark plugs, no.3 catalytic converter, no. 4 loose or damaged gas cap and no. 5 EVAP purge control valve.

Learn more about CarMD VHI Report

Please submit your information to have out Vehicle Health Index Data Services Team connect with you shortly.

2018 Vehicle Health Index

Highlights – Check Engine Light Insight at a Glance

According to CarMD, during 2017 the following were the five most common check engine light-related car repairs and associated average repair costs, including parts and labor. If left unrepaired, each can negatively impact fuel economy and harm the environment.


  1. Replace oxygen sensor – $238
  2. Replace ignition coil(s) and spark plug(s) – $367
  3. Replace catalytic converter – $1,271
  4. Tighten or replace fuel cap – $26
  5. Replace evaporative emissions (EVAP) purge control valve – $147

Don’t panic when the check engine light comes on, but get it diagnosed ASAP. It can be as simple as a loose gas cap. But a flashing check engine light can indicate a more serious problem such as an engine misfire that needs immediate attention from roadside assistance.

Diagnostic trouble codes (DTCs) are 5-digit alphanumeric codes that identify the trouble area and help identify why the check engine light is on.

The 1st character is a letter that defines the main system where the problem occurred. The 2nd is a number that identifies the type of code.

The 3rd IDs the affected system, and the 4th and 5th characters define the section of the system that’s malfunctioning.

The most common DTC in 2017 was P0420, which indicates Catalyst B1 Deterioration that often signifies a faulty oxygen sensor or catalytic converter.

According to CarMD’s findings, in 2017 the oxygen sensor remained the no. 1 most common check engine light culprit, following by no.2 ignition coil and spark plugs, no.3 catalytic converter, no. 4 loose or damaged gas cap and no. 5 EVAP purge control valve.

Vehicle Health Index


Learn more about CarMD VHI Report

Please submit your information to have out Vehicle Health Index Data Services Team connect with you shortly.