This is perhaps the most mis-understood issue facing the auto repair industry today. The term diagnostics or diagnostic time refers to the time needed to find the cause of a problem or warning light.

The problem may be found quickly, or it may take up to several hours. As technology has advanced, so has the strategy of diagnosing automotive systems. Today's cars are extremely complex vehicles with on-board networks of computers that interface with each other. The computers, or control modules, use a variety of sensors that perform specific tasks like measurement of engine or air temp, vehicle speed, and oxygen content of exhaust gas.

When any symptom or warning light becomes present and service is required for your vehicle, the first step will be providing a good description of the symptom to the service writer at the desk. Next, a technician will begin diagnosing the problem.

If it is found quickly, as in the case of a coolant leak (which may be the cause of overheating, strange smells, improper heat delivery, rough engine operation, etc.), the charges will be less (usually a shop has a minimum charge). If the problem is more involved and/or is intermittent, it will take more time, specialized tools and equipment, and a thorough understanding of the system in question.

This is where most of the confusion may start on the part of the customer. I have heard many times when discussing the results of a diagnosis with a customer, "Why am I being charged? You didn't DO anything?!"

The fact is, even though the problem may or may not have been repaired yet, something WAS done. Time was spent in an effort to diagnose the cause of the concern, and at this point, a solution may have been found that will require a specific repair, there may be a request for more diagnostic time to continue to track down the problem, or there may be a suggestion to continue to monitor the symptom until it gets worse.

In any case, the time spent is referred to as diagnostics. Often the diagnosis is the hard part of the repair. Determining what is not working correctly can be challenging. Much like a doctor performs a variety of tests to gather information and ensure the correct diagnosis is made, so does a well-trained automotive professional.

I hope I have helped to clear up some of the confusion so, in the future, you can more easily understand the steps that were necessary and the charges that appear on an automotive repair bill. As always, I welcome your feedback and any specific questions you may have. I realize that my space is limited and there may be questions you have about a particular experience you have had.

Questions? Post comments here or contact Ridge McCoy, service manager at Alki Auto Repair, at ridgealkiauto@comcast.net or 935-8059.