Best Auto Repair, Marietta

  • 850 Sandy Plains Rd, Ste 3 Marietta, GA 30066


770-422-0919 | 850 Sandy Plains Rd, Ste 3 Marietta, GA 30066


September 2022

The Speedy Difference

What Exactly IS a Diagnostic?

We have found that most customers don't really understand what is involved in diagnosing a problem with their transmission. One of the misconceptions about car repair is the diagnostic report.

What exactly is a diagnostic report? Many people think that we just hook the computer up and it magically tells us what is wrong with your car. Unfortunately, it isn't that easy--or magical. A diagnostic computer is certainly helpful, but it does not tell us what is wrong with the car. The diagnostic computer gives us data from a report, and then our trained technicians interpret that data along with other observations of the vehicle. For example, when your check engine light comes on, we can receive a few diagnostic codes. And oftentimes, there are more than one! These are 5-digit codes that often describe a problem that the car is having. These diagnostic codes are a starting point for us to begin finding the source of the problem. After a diagnostic report, we get a report that tells us a particular issue, but it does not specify the direct cause of the problem. It is just an indicator to where our technicians should begin their investigation.

The next thing the diagnostic computer gives us is called "freeze frame data." This is an overview of all the sensors and data and includes everything that was going on at the time the code was initiated. Our experienced technicians can use this report to help figure out what may have happened to cause the problem. We can monitor live data from every sensor on the car and watch for anything out of the ordinary. We can also test individual components and run various tests by making a change and watching the computer data to see the result. All of these can help us narrow down the source of the problem with your car and your transmission. Sometimes the computer tools can take us right to the exact problem. Oftentimes, we will need a little more investigating because the computer does not give us enough information. At this point we look under the hood, and we do a visual inspection. We look for anything abnormal such as smoke, burning wires, broken seals, clogs, etc.

After a diagnosis, we may have to take things apart and inspect them. Then we test individual components. Most of the time, we can get enough information to find the problem with just a few steps. There will be times when we need to spend more time with a vehicle. We may need to run tests under various conditions (driving tests, gear shifts, etc.) Common testing to vehicles that helps us determine the transmission problems include driving the vehicle with a cold engine, driving the vehicle with a hot engine, checking the vehicle at different highway speeds, and also in-town driving. All of these are normal conditions for everyday driving and help us understand your car.

When you bring your car to Speedy Marietta, you can help us with the diagnosis by sharing as many details as you can about the problem with your car. Tell us when the abnormal conditions happened and what we can do to recreate the same issue. This will help us make sure we are testing the correct problems. This is the best way to help us determine the source of the transmission issue a lot sooner. One of the best ways to prevent transmission failure is to have annual inspections. We perform a complete diagnostic as well as replace your vehicle's transmission fluid for optimum performance. And don't fret if you ever feel like your transmission isn't performing its best -- just bring your vehicle in to Speedy Marietta and our highly trained technicians will complete a complete diagnostic. We're here when you need us, and we're here to help.

See below for links to previous blog posts:

March 2022
November 2021
July 2019
June 2019
October 2018
September 2018
August 2018
May 2018
April 2018
March 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017

Speedy Transmission by CS Offers Auto Repair Services You Can Count On!

ASE (Automotive Service Excellence)
BBB Accredited Business
Free Wifi
Christian Fish
Cobb Chamber of Commerce
Synchrony Car Care
Car Care Aware


Without a doubt, best transmission shop. 100% trust these people with all vehicles I own. Way better than AAMCO & cheaper. Everyone was very nice & friendly professionals. They stayed in touch with me as my cars transmission was being rebuilded. They treated me as I was importan
, 10/05/2021

Very helpful. Very kind! Good hearted staff?
, 09/22/2021

In today's society having an expensive repair done can be a gamble because most people put on a good front until you've spent your money then do questionable work, Which is why most people rely on a good review when making a decision where to take their vehicle. I chose speedy Marietta based on their customer feedback and was not disappointed. They did a great job rebuilding my transmission it drives and shifts in a way you know a professional with experience did the job. The pricing was fair and the work was done in a reasonable amount of time. I will definitely use their services again and highly recommend them to anyone in need of repairs .
, 06/22/2021

Great staff. Owner is awesome. Staff is awesome. Highly recommend. Great honest transmission shop!
, 05/15/2021

Speedy Transmission is an excellent transmission repair shop. The people there are great to work with. The main gal at the deck is extremely knowledgeable as well as professional and a nice person. She is either the owner or employee but if she's an employee she needs a raise. I am especially appreciative of this shop as they came highly recommended by a friend of mine and the only transmission shop in the area that I know who were willing and able to work on my vehicle. Evidently my vehicle (a 2012 GMC Penske box truck) has a transmission that is more difficult to work on than normal and other shops in the area had declined to even give me a quote as either their bays weren't big enough or the transmission itself was too difficult. Thanks everyone at Speedy Transmission.
, 05/08/2021

Great shop with very knowledgeable & honest mechanics with very reasonable prices. I've used them several times & send people there as often as I can
, 05/07/2021