Book Mercedes-Benz computer diagnostics at our Haines City shop. Same technicians, same bays, every time you come in.
31600 U.S. 27, Haines City, FL 33844
Monday to Friday, 7:30 AM to 5:30 PM
When a scan tool pulls a stored code off your car, what comes back is a number and a short description: a lean condition, a misfire on cylinder three, a circuit reading out of range. That tells us where the car noticed something wrong. It doesn't tell us what caused it. One lean code can come from a vacuum leak, a tired fuel pump, a dirty mass airflow sensor, or an exhaust leak sitting upstream of a sensor. Replacing the part named in the description works out sometimes. When it doesn't, you've bought a part and you still have the problem.
So the code is where we start, not where we stop. From there a technician watches live data while the engine runs, compares those readings against what the manufacturer says they should be, and tests the actual circuit or component with a meter, a scope, a pressure gauge, or a smoke machine. Sometimes it means driving the car until the fault shows itself. That testing is what turns a system into a part, and it's why diagnosis takes real time. It's skilled labor with real equipment behind it, the same as any other job in the shop, which is why it gets billed like one.
A free code pull at a parts counter is a useful thing to have. It tells you a code is stored and roughly what system it lives in, which is more than the dashboard gives you, and it costs you nothing. It's a starting point. What it isn't is a diagnosis, because nobody put the car on a lift, watched it run, or tested anything. If you already have the code, bring it. We'll use it. We'll just keep going from there.
Here's what paying for diagnostic time actually buys you. A named cause, meaning the specific failure we found and how we confirmed it, not a system and not a maybe. Photos of it on your phone from the digital inspection, taken on your vehicle that day. And a quote to fix it. Whether you do that repair, with us or anywhere else, is a separate decision and it stays yours. Plenty of people take the answer and go think about it.
The math on this is simple. Diagnosis costs what it costs, once. Guessing costs a part at a time until something works, and none of those parts come back. That's what you're really protected from here: paying for repairs that don't fix anything. Whatever we do fix carries a 36 month, 36,000 mile nationwide warranty, and every one of our six shops works the same way.
Our Team
August 2026
The vehicle owner reported an oil leak and a message indicating to check the oil level. Upon checking, no oil was visible on the dipstick, and leaks had been observed for about a week.
The technician found that the oil pan gasket, valve cover gasket, and oil separator were contributing to the oil leak. The team at our Haines City shop removed and replaced the oil pan gasket, valve cover gasket, and oil separator to address the leaks. These components were identified as the sources of the oil loss.
After the repairs, the oil leak was resolved, and the vehicle's oil level warning light no longer appeared.
If your oil level warning light comes on, check for visible leaks and inspect the oil level immediately. Addressing leaks early can prevent engine damage and costly repairs.
Johnnies is currently the only shop I will let service my Mercedes benz c300. I take very good care of my car and I use Johnnies because they treat my car as if it were their own. Pricing is better than other places nearby, their customer service is exceptional and the lounge area is 5 star hotel quality.
Shane Wise
Verified Google Review
It is hard to know where to begin when you are overwhelmed by professionalism and finding a garage with folks that care and listen. I can verify that the other reviews commenting on the inside of the “waiting room “for lack of a better term is unlike anything I have seen before. Snacks, relaxer chairs😉, television , the shops history listed on the wall … and best of all they’re honest. I brought in a 2016 Mercedes Metris with a breaking issue. I was genuinely concerned only because we had owned the vehicle for less than two months and it could have been anything. Usually…with any MB, anything that breaks = lots and lots of money to repair! The Mercedes-Benz dealerships were quoting us anywhere from two to $300 an hour just for a look and that that much an hour for labor! 😖 Their service departments are so overwhelmed and overbooked that one of them only had one mechanic for 76 Metris’s on site that needed repair. 😖Need I say more. So I looked online and saw the reviews on Johnny’s. From the first call … it was great!!! we drove down and the gal that took care of us and checked us in was wonderful. I sent them some additional potential recalls that may or may not have been relevant to the issue with my vehicle. Had I done that to another repair shop it probably would have been completely disregarded ignored and probably deleted . However, that was not the case here. Everything I found and texted to them wad was responded to with courtesy and a “thank you”.. wow! We were treated with good old-fashioned politeness that I haven’t seen or experienced in years to be totally honest. So now let’s talk about price. The initial problem could have possibly been would a small fortune to repair at a Mercedes-Benz shop. However, the issue they found was easily and quickly repaired, and I also had them do a preventative brake flush for the system as well. To get out of a shop with a Mercedes-Benz under $300 is rate these days. But Johnnys did it. I am extremely grateful. When I thought the reviews were too good to be true well guess what they’re not. They are true. So, if you have any issues at all before you spend a small fortune at a dealership charging anywhere from two to $300 an hour go to Johnny’s first. It was definitely worth the ride from Solivita.
ann miller
Verified Google Review
Our Mercedes C280 needed the A service. Friendly staff, short wait, and reasonable price. Do recommend this shop.
Hartmut Berns
Verified Google Review
Pick whichever one is easiest to drive to.
ASE Certified Technicians
ASE certified techs working on your vehicle
Flexible Drop-Off Hours
Convenient service options
20+ Years
2 decades of trusted service
