Auto Service World
News   December 27, 2023   by Auto Service World Staff

How Much is a Diagnostic Test on a Car?


Seeing a check engine light on your dash is never a fun experience. Most of the time, you will have little idea what caused the warning. If you have thought about taking it to an auto tech to run a diagnostic scan, you may have wondered about the cost of the test. Here’s what you need to know. 

Cost of Professional Diagnostic Tests

Some repair shops will scan your car for free, but most charge for the service. Having the codes checked at a repair shop will usually cost around $100. You can pay a little less or a lot more, depending on where you are and where you take it. For example, in many places, dealerships are the most expensive option while chain stores often have a set fee.

When a technician hooks your car up to a scanner, it reads any OBD codes sent from the car’s internal computer system. This may not give a precise answer to what is wrong, but it can usually identify the vehicle system that is causing the problem. For example, you may find a code indicating an exhaust leak, so you know where to look. A visual inspection is often part of the diagnostic process. 

When To Get a Scan

You may consider putting off a scan to avoid or postpone repairs. However, because modern cars have so many computerized components, a warning light could indicate any number of problems. Some are serious, while others can be as simple as a loose gas cap. 

While there is always variability, a good rule of thumb is that if the light is solid, you can drive to a safe place before worrying about the scan. However, if the light is flashing, you want to check it out right away. Failure to stop immediately can cause significant engine damage that will cost far more than a simple diagnostic scan. If in doubt, get it scanned at the soonest opportunity. 

Code Readers Are a Practical DIY Option

An at-home code reader for cars is a practical and affordable solution to professional scans. If you are relatively handy and know your way around an engine, you might consider taking your car to an auto parts store or purchasing an OBD scanner. In most cases, you can get a good-quality scan tool fo about the same price as a single professional scan, and now you have it for the next time the check engine light comes on. 

These offer various features, which typically include a display of the code or codes that triggered the light and a way to clear the light. Simply plug the adapter into the OBD2 port on your car, typically located under the dash on the driver’s side. With the push of a button or tow, you can get a detailed report of what codes the computer is throwing and clear the check engine light. 

Your car’s computer provides a lot of information that can help you diagnose problems. Shop online auto parts stores for products such as the Innova OBD2 code reader to find out what caused your check engine light to come on and then get the parts to fix the problem.