Some Barnhart motorists are confused by Kevin’s Car Care charges for diagnostic services for a vehicle repair. Many services at Kevin’s Car Care and other Barnhart automotive repair shops include diagnostic fees.

When you take your laptop into a St. Louis computer repair shop for a problem you’ll likely have to leave a deposit for diagnostics. When we visit our Imperial doctor for a medical problem, we’re paying him to diagnose our ailment and of course for the tests that go along with it.

So receiving a diagnostic charge at Kevin’s Car Care for a tricky automotive problem shouldn’t be a surprise. In the St. Louis area, automotive diagnostics can cover quite a range. If you hear a noise in your sedan brakes when you slow down in rush-hour traffic on a busy Missouri expressway, you pull off the next off-ramp and take a quick visual check. That is usually enough to know what needs to be done. If you’re having an intermittent problem with your sedan engine, Kevin’s Car Care diagnosis may be much more involved.

Much of the St. Louis public’s confusion comes when the problem involves the check engine light. The check engine light comes on when the engine management computer has sensed a problem.

There’s a common misconception among Imperial, Arnold, and Festus drivers that the trouble code tells the Kevin’s Car Care technician exactly what’s wrong. Why then is there a diagnostic charge, the scanner just gave the diagnosis?

Reality is more involved than that. The computer monitors many sensors throughout the vehicle. When one of these sensors has a reading that’s out of parameters, the computer will record a trouble code and turn on the check engine light.

The sedan computer’s trouble code just tells the Kevin’s Car Care technician what engine parameter is out of range – not what’s causing it. The technician needs to determine the underlying problem that’s causing the symptom.

There are many problems that could cause a troublesome sensor reading for Kevin’s Car Care Barnhart customers. The Kevin’s Car Care technician makes a list of the most likely causes and begins tracking down the source of the problem.

St. Louis service centers subscribe to databases that document possible causes for a given trouble code. They outline procedures for confirming a diagnosis and provide the documented fix. These databases are specific to each vehicle and engine combination.

Some diagnoses are quick and easy. Others are more involved and difficult. Of course Kevin’s Car Care wants to figure out what’s wrong with your sedan and get you back on the road as quickly as possible.