Importance of a full diagnostic

Why does my vehicle need a diagnostic test?

The least expensive way to repair your car is to have a professional mechanic perform the proper testing on it to identify the root cause of a warning light. The best mechanics at this process are often referred to as Diagnosticians.

Parts stores and a few auto repair shops have promoted ‘free diagnostics’, where they plug a code reader into your car and then sell you a part or work based on the fault code that is present. However, this is not truly diagnosing your car. The truth is that they are selling you a potential repair based on likely causes for the warning light. Simply put, it’s a guess. This often leads to them selling or installing multiple different parts that don’t actually fix the issue and end up costing you more money in the long run than having it properly tested.

Fault codes identify which systems are having issues, but they don’t identify what components are actually failing, or why. A professional mechanic will use those fault codes to formulate a plan on what tests and procedures are required to identify the root cause of the warning lights. Sometimes diagnostic computer software will help by providing a troubleshooting tree, or even a guided test plan based on the fault codes to assist a technician when performing testing. With as many as three dozen different computers in your car, all talking to one another, this can be a time-consuming process.

And not all diagnostic computers are created equal. There can be anywhere from a cheap code scanner for $60 to a factory diagnostic computer that costs tens of thousands of dollars. The factory computers often log directly into the manufacturer’s servers to assist in testing & programming. The more specialized and advanced a repair shop is, the more advanced computers they will invest in. This larger investment allows them to more accurately and efficiently diagnose issues in cars and properly repair them.