CarMD Review – Automotive Vehicle Diagnostic Scan Tool to Avoid Scams



carmd logoYou take your car in for routine maintenance and the mechanic comes back saying that the car has about five different issues you weren’t expecting. You want to believe that they are telling you the truth, but mechanics in general don’t have good reputations so it’s hard to take them at their word. Does this sound familiar?

If you’re like me and don’t know much about cars, chances are that you’ve run into this situation more than once. By now you probably dread taking your car to the mechanic.

This is where a product like CarMD comes into play. The folks at CarMD developed the product to put more knowledge and power in the hands of the car owner, rather than the mechanic (where you can easily fall prey to a scam).

carmd reportJust like so many other things in life these days, all of the electrical components in your vehicle run from a computer chip. Even your engine sends codes to this chip when something is wrong. Before CarMD, the only way to read these codes was to bring it into the mechanic or dealer and use their equipment.

If you’ve ever paid for a “diagnostic fee” from the mechanic, you know that the price for the test alone can be pretty steep. And they’re not even fixing anything yet. You’re paying them to hook up a machine that pulls the codes from your engine to figure out what the problem is.

CarMD’s device allows you diagnose your car without taking it to the mechanic, saving you time and money. I was fortunate enough to receive the CarMD and test it on my cars. Here’s what I found out about it.

How CarMD Works

CarMD is a pretty straight forward product. For the total cost of $119, you receive the diagnostic tool as well as the appropriate software. Below is a step by step breakdown of how the process works.

  1. Find your CarMD connection. This could be the hardest part of using the CarMD product, if not for the helpful guide on their website. Instead of trying to find the connection myself, I just went to their website to input my make and model, and CarMD popped up a nice picture and description of where the connection should be for both of my cars. You can even run the search before creating an account. Be sure that when you go out to your car, you write down the VIN number. You’ll need to type it in when you sign up for a new account on the CarMD website. The VIN number can be found in the corner of the dash on the driver’s side, on your car insurance card, or on your registration paperwork.
  2. Connect your CarMD and turn the ignition of your car “on.” Don’t turn on the car’s engine, just turn the key to the “on” position, like you would if you wanted to put the auto windows down. You have to do this within 10 seconds of hooking up the CarMD device, or you’ll get an error message. If you get a “good” connection, it’ll beep twice.
  3. Wait for the beep. Wait until the CarMD beeps 4 times. This means that it has successfully retrieved your car’s diagnostic information. Sometimes it takes a while for it to beep, so just be patient.
  4. Load the CarMD software and sign up at If you’re good with computers and installing software, then this step should be a breeze. The nice thing is that it’ll work on both Windows-based PCs and Apple Macintosh computers. Once the software is loaded up, plug in the CarMD via USB port, sign up for a new account on, and view your test results.

I followed these steps when using the product on each of my cars. To help further inform you, I videotaped my experience.

My Experience with CarMD

Watch this short video to see how I actually used the CarMD device.

1. My 2006 Hyundai Sonata

I connected the CarMD to the Sonata after I located the hook up under the steering wheel. Luckily, I got a GREEN light. When using the CarMD, a GREEN light is your best friend because it indicates that no problems were detected. That doesn’t necessarily mean your car is perfect, but it does mean that the computer in your car isn’t trying to tell you anything.

2. My 2003 Nissan Xterra

This car was a different story. The CarMD pulled a P0328 code from its computer. I got the report from the CarMD website, and it explained that this code meant that the engine’s knock sensor is going to go bad.

I’m not a car person, and I had no idea what a knock sensor was. Even after Googling it, I’m still a little confused about what it does. I think it senses if the engine is literally “knocking” or, in other words, the engine is not secure to the engine block. Car people, please correct me if I’m wrong.

Anyway, after reading a lot of forums online, it looks like the jury is kind of out as to whether this is a serious problem or not. From what I gather, it can cause a decrease in engine performance, fuel economy, and acceleration. That actually makes sense, because I’ve always noticed my Xterra has really bad acceleration and less than desirable fuel economy. What do you think? Should I replace it? Will it screw up my engine over the long term?

As you can see, I came away from the experience with more questions than answers. That being said, I’m glad I had enough information to research the problem on my own before paying a mechanic for the diagnosis. So, what was my take-away from using the product?

Pros of CarMD

I found that CarMD had several things going for it:

  1. Simple to Use. If you’re not completely helpless on a computer and if you can find the 16 pin input to plug in the CarMD on your car, the whole process is fairly simple.
  2. Informative. It does give you useful information such as the engine diagnostic codes, estimated repair costs, and manufacturer recalls.
  3. Helpful Website. The feature on their website that helps you find the connection on your particular make and model is really handy.
  4. Convenient Size. The CarMD device is very light and portable. It’s small enough to keep in your glove compartment.
  5. Compatibility. It’s compatible with PCs and Macs. I had no problem installing the software on my Mac and it read the data quickly when I registered on the site.

Cons of CarMD

There are a few drawbacks that should be considered before you purchase CarMD:

  • One Car at a Time. I had to grab the data from each car and load it onto the website separately. This was a bit tedious and time-consuming. I could not figure out how to upload both at the same time.
  • Technical Descriptions. The descriptions given of the engine codes were not the most intuitive for the laymen. I had to do a lot of research online to figure out what a knock sensor is and if I should be concerned about it.
  • Dark Screen. The screen doesn’t light up. If you needed to check it at night, you’d have a hard time reading it. For $119, you’d think they could put a backlit screen in there.

In addition to these issues, I think that some of the codes pulled might not be necessary to take action on. People might spend a lot of money without truly needing to replace whatever the engine codes recommend. In my case, it seems like a judgment call, and I’m not qualified enough to make that on my own. I’ll probably end up consulting a few car people who I trust to find out if I should replace the knock sensor right away, or wait a little bit.

Final Word

Obviously, I wasn’t happy to see that my “knock sensor” is bad in my Nissan Xterra, but at least now I am aware that there’s a potential issue.

Admittedly, the $119 price tag might deter some folks from rushing out to buy the CarMD, but overall, it can definitely save some time and money by empowering consumers to know about potential issues before they become bigger concerns. It would be a great gift to give someone, and I would be really happy to receive it as a gift myself.

As far as this product paying for itself, ease of use, and the amount of information and tools on the CarMD website, I give it an “A.” They made the process very simple and I had no problems from start to finish. CarMD is a quality product, and it’s a product you should consider buying if you have an older car (but no older than 1996), and you’d like to get a leg up on potential repair issues without relying on the mechanic to give you an honest opinion.

Have you, or someone you know, used CarMD? Was it worth the price? Please share your experiences in the comments below.

Comments Disclosure: The below responses are not provided or commissioned by the bank advertiser. Responses have not been reviewed, approved or otherwise endorsed by the bank advertiser. It is not the bank advertiser's responsibility to ensure all posts and/or questions are answered.

  • Mac

    I recently bought a competitors device that does the same thing, and it’s o-k. It does the job, but it won’t be used that often. I got it because my car went into “limp mode” when I accelerated too quickly. If I use the device within the next day or two I will get a few error codes. Then I check online to get a very short description of the error code. After that I google each description and I get some advice from other users who ran into the same issue.

    According to my research, my car was experiencing a popular issue and I was going to have to spend $400 to replace a part on my Sonata. However, my father-in-law took a look at it, proceeded to tighten up a screw and the issue was completely resolved. Interesting. So this device CAN be useful, but you’ll end up having a mechanic looking at the car anyway.

  • viga

    Car MD appears to simply be a low-end OBD II code scanner. Similar code scanners have been on the market for years.

    Simply retrieving a code is not enough information to resolve an issue, however. That said, it sounds as if this product comes with some potentially interesting access to technical information provided by ASE certified mechanics. I would hope that this information would help people avoid…say…replacing the sensor indicated by the code versus actually finding and fixing the problem that’s being indicated by the sensor. However, without access to the information that comes with the product, I can’t say how good that information really is.

  • SeraAnna

    I purchased the Car MD after reading about it’s Edison Award win. I cracked it open for a friend whose Check Engine light went on. It was so easy to use and so empowering for 2 women to be able to diagnose a car issue. As it turned out her gas cap was not on tight enough and it caused the light to come on – who knew??? It saved her a trip to the dealer and convinced me to buy another Car MD for myself. So cool!!!

  • Brian Boyce

    I got a CarMD for this last christmas and it seemed like a such a great device! I used it when shopping for a used car for my daughter. Like you mentioned, I was able to make a better decision in which car to get her, to see if there were any hidden internal problems with the car. Such a great device! Right now the CarMD sits in my daughter’s glove box and i have some peace of mind knowing she has a device that can help her understand her car just an arms reach away.

  • martha jarreta

    First of all credible repair shops don’t employ mechanics, they employ technicians. What’s the difference? A mechanic changes parts a technician diagnosis the problem and fixes it. As for the diagnostic charge”” that shops charge is because the have to pay a tech to scan the car, pay for the scanner itself, pay for electric, and pay for everything else they purchased so they are able to work on vehicles. Have you ever priced quality tools and equipment? Also most of the repair shops that I know only install the parts they purchase due to warranties and such. So my advice would be to install your own part if you buy it at the DIY (aka Do It Yourself) store. Bringin you own parts to a repair shop is like taking your own hamburger to McDonalds. FYI if your vehicle has an error code more than one thing could be wrong with it. Also with all the new hybrid cars you should seek out a qualified shop or you could end up costing your self way more money in the long run.

  • Andy Robinson

    Save your money and buy a unit that can reset the Check Engine Light. CarMD is only a code reader and cannot reset the light. What good is it to know the problem, fix the problem and still have the light on.

    • K Sook

      My maintenance light was on for my oil change (which I do myself) and was tired of always having the light on even after changing it. I looked through my Honda Accord car manual and they had detailed descriptions on how to turn the lights off. You could check your manual before you buy the unit.

  • not given

    I thought you could reset the check engine light by unhooking the battery, then hooking it back up.

  • cubical

    You can reset the light by disconnecting the battery,keep in mind that will also clear the trouble code.If the problem still remains the same code will be sent to the computer.

  • John Ferris

    to martha jarreta : Is it not politically correct to call a mechanic a mechanic anymore? They are now a technician?? I guess I have missed the boat. It seems that someone has rattled your chains and may have insulted you based on you telling them what is on your balance sheet, electric, labor, rent etc.

    I bought the car md, use it on all 4 cars and go to youtube, find the video I need and I will usually fix the problem myself and save $75 for a diagnostic and $80 an hour to fix it and not come home with something else wrong.

    Why is it every time I go see a technician I have something else wrong when I get back home? Interesting isn’t it?

  • Vic

    I got a OBD II code scanner at Amazon for twenty bucks and can reset. The problem is these scanners is they are dumb ,they read codes, not troubleshoot those codes. For example a mechanic will get a code, replace the offending part and still get the code. Then he finds the real problem…a short! Your out 400 bucks!

    Happens every day!

  • Kira Botkin

    Engine knock has nothing to do with the engine not being secure in its mount! It is called knocking because it makes a sound like someone rapping on a metal door, not because it is knocking around. Knocking occurs when the air/fuel in one of your engine’s cylinders is not igniting at the right time. It can destroy your engine if it keeps happening which is WHY you have a sensor – you should definitely take your car in!! It does degrade your fuel economy because the cylinders aren’t getting the boost they need to be the most efficient they can be, so they need to use more gas to create the same amount of “go” – but also if it keeps happening a lot it can damage your engine. You might also want to have the transmission checked out if your acceleration is bad from 30 and above or it seems to be hesitating before changing gears.

    I own a car computer that I bought for about $70 off Amazon – I agree with Vic that it just reads the codes, you have to do some research to find out what is going on, which it sounds like CarMD will help you with. But sometimes it is simple to fix, or you want to find out if this is something catastrophic that must be dealt with immediately, or if it can wait until payday. :)

    Ours has paid for itself several times over, not least because both my and my boyfriend’s Pontiacs got Check Engine lights that we checked with it and fixed ourselves The code for both cars was for air entering the fuel system – and while a mechanic would have run an expensive fuel system diagnostic looking for leaks, we thought we’d at least try the cheap solution which is to replace the gas cap. (The seal can go bad and let air in.) We spent $20 on each gas cap, solved the problem, and saved a $200+ visit! If you try this, make sure to get one from a dealership that is specifically for your make/model of car – some car models can actually tell if you got a cheapo one from Auto Zone and will “reject” the cheapo gas cap.

  • Erik Folgate

    Wow, thanks everybody for the tips! I’m definitely not too much of a car guy, and I am still a little skeptical if I want to replace this knock sensor if it costs hundreds of dollars, but maybe i should after reading Kira’s comments.

    I think these little code reader tools can be helpful to help prevent catastrophic collapse of your car, but for the most part, they aren’t necessary if you get your car checked out regularly. It’s just nice to have a heads up before the mechanic starts giving you their laundry list of things you should have done.

  • Matt Breed

    It’s funny, my co-worker was saying just the other day that she had to take her computer in to have it looked at. I know a bit about computers, but am definitely no expert. I told her that regardless of whether there actually IS something wrong with it, they will find something…not unlike taking your car in to have it looked at.

    Luckily, I have a lot of friends that are very computer savvy, I wish I could say the same about vehicularly-inclined friends. If you don’t trust your mechanic, you NEED a new one.

    • Toms


    • Valcour


  • Sharon Lear

    I purchased a CarMD in February for my son in law. I found he already had a reliable system check, so I called the same day and tried to cancel the order. They said it had already been shipped. I got a return slip to ship back UPS. Proof was shown they received back at CarMD in 3 days. This was the first of March. I have called they 4 times, but have not received credit to my credit card. Each time they promise to return it, but no credit yet. I highly recommend you do not buy this product!

  • Green_onions62

    I’ve read all of comments, but i still have yet to read one on trouble shooting, Transmissions
    does the CarMd covers the whole car system?.

  • Anonymous

    I’ve order one for myself and to be honest I’m sold on the idea of have a friend by my side to help along the way to make a long story short here: I’ve a 2000 saturn sw2 it has about 167,00 miles on it and honestly I’m a budget here now what saying without a computer like this carmd its going cost me about 75 to tow it to a shop pluse a other 100-150 to finger out what wrong with it and honestly here I’ve aldy now something is stuck in the transmission and the waterpump is miss up and stater screw up and do be honest its going to cost me more to fix it then its worth but with carmd i can know what is wrong with it in detail and could finger how much its going to cost to fix it but honestly its trash and I’ve a 2011 honda fit sport and I want me make sure its running at pick performance level at all times so say the lease here i think everyone should have one

  • Trevordeo

    I order two CarMD and did not work no respond I made many calls/email,s no one contacted me so I returned them 4 weeks ago still no answer they took my money I think it is a scam

  • Tis

    I bought CARMD two months ago. It already save me money huge. I take it with me on vacation and just around town. Thanks CarMD!

  • Anonymous

    I purchased the CarMD, Did NOT work. Not much help from the techs I talked to, returned product and received another which also didnt work, could not get past step 2, I did finally talk to someone and he said “cant help you, nothing we can do to fix the problem” returned the product and they didnt refund the shipping, I do not recommend this product.

  • Ar

    They say they have a money back gurantee, can return for any reason and a refund will be issued. What a crock! I returned a unit 2 months ago, still waiting for my refund!!!!! The keep saying sorry you should have it in 7 – 10 business days. Still no refund. This unit doesn’t detect as many issues as the TV add says it does, for the money don’t buy!!!!!!!!!!!!!!!!
    Your local auto zone can hook up a scanner to help you diagnose problem free of charge!

    • WarnerRobins

      Just wondering if you’ve now received your refund?

  • Mkflagg

    not happy at all

  • bakedpotato

    CarMD reads what is stored on your cars computer, that’s why you don’t start the engine, just turn the key to the on position.
    As far as diagnosing a transmission problem, well probably not but I don’t know that for sure. Try reading the information on the CarMD website and see if there’s any information about what exactly CarMD can and will diagnose.
    As far as engine knock goes, maybe try a tank full of high octane gas instead of the 89% low octane and see if that helps with the engine knocking.

  • Anonymous

    I really like my CarMD. It alerted me to a recall notice on my 07 subaru. It was actually pretty critical and involved leaking oil and fire!

  • Rob

    I bought one and wish I had my money back so I could by one I could use as much as I wanted too. This code reader is limited to 6 uses per month and I own 5 cars! I also don’t like having to go online an register the car and have to get the vin and milage to find out the code. What a rip-0ff.

    • Suzderra

      geez I feel like a moron for buying it… didn’t diagnose our dodge ram fuel filter problem and we got stuck for many hours waiting for a tow truck…….we have many vehicles and two left us stuck on freeways waiting for a tow truck….this stupid thing didn’t diagnose anything

      • Suzderra

        listen 2 their commercials: a guy says ‘cadillac’ convertor……can he just be literate and say :catalytic ??? if you have people on commercials misstating words than how good is is your product?

  • Lskoebli

    Maybe this product has some useful purposes but it certainly is not any good as far as doing a “PINPOINT TEST” on your problem. Must be done by a qualified technician with the proper testing equipment. Diagnostic testing is often the most time consuming part of your car repair.

    • Smworlow

      plus now car md is advertising on the low end channels…just a bogus company..dont fall for their crap

  • Suzderra

    just a few words: don’t buy it

    • bdkennedy11

      An explanation as to why would have been helpful.

  • Copie

    After months and a lot of money trying to fix
    Issues with my car, I purchased the CARMD
    The day I receives the unit it CODED 2 problems
    After fixing them, WE HAD NO MORE ISSUES

  • Eric Leevon


  • Eric Leevon

    The same service is available at most national chain parts stores. Pep Boys, AutoZone, O’Reilly’s, Advanced, NAPA, Carquest all offer a code reader service that does exactly the same thing. The difference? It’s free from the parts store. As for the TSB “service”, enter the make and model of your car into any search engine followed by TSB, and away you go.