What is the typical cost for a computer diagnostic test because the check engine light was on? I live in the Twin Cities, Minnesota. Thanks

Go to any AutoZone and they’ll pull the codes for free.


Take it to a chain auto parts store like Advance. They will loan you a code scanner for free and help you figure out what’s wrong, too. They do it to sell you parts, though you aren’t required to buy any. Post the results here and we’ll help you figure it out.

If you already had the test done and want to know whether you were snookered, I can’t help you.

it’s free at most auto parts stores. Of course all you will get is the code, which is not the same as diagnosing the problem.

As others have said, you can get it done for free at most auto parts stores. However, if the code indicates something complicated, you may want to pay a mechanic to take readings for you. Sometimes the auto parts store’s readers will only give you one code, and a mechanic’s reader will give you up to three codes. Sometimes you get what you pay for.

When you pay to have the codes read, the diagnostic fee can cost between $40 and $80. It depends on the hourly labor rate the shop charges.

If you get your codes read, post them here. Make sure you get and post the numerical codes, not the mechanic’s or store employee’s interpretation of them.

As noted the code will tell you why the light is on. It will not tell you how to fix it. Usually there is at least two possibilities, one being the part (say a bad spark plug) or it may be the sensor that thinks it is a bad spark plug. In any case it rules out a lot of things by knowing the code.

A site which might help,, provides estimate ranges for a wide variety of selectable automobile repairs and work which can be expected in specific zip codes. If nothing more, it is a good starting point and provides a basis for judging if the shop/dealership is reasonable at the start.