AndrewFerg

Hey all,

I've used the forum search and can't find a recommendation for an OBD2 scanner for home use for my 2018 AMG GTC and I'd love a recommendation. I know Mercedes has peculiarities so not all OBD2 scanners work. I stopped by AutoZone and their scanner didn't show any codes when I definitely had one. Sorry if the answer is here and I can't find it.

Andrew

Stenzel-Germany

Hi Andrew,

Depends on what exactly you want to do.

The OBD socket is standardized, but only for the ECU and only partially.
A simple OBD scanner is sufficient to read engine parameters / errors or to delete an engine error light.
Just be careful, some have saved the manufacturer logs and output the errors in plain text, some only as code. Impractical to google first. :-)

There are also OBD BT dongles with mobile apps. Some seem to work fine. Have no experience here.

For foreign vehicles or simple, quick ECU codes I use a $25 OBD scanner (Konnwei KW 310) This can also log data / sensors.
Outputs the error directly and also writes in German. :-) We understand each other.

For everything else you need a professional diagnostic system, because every manufacturer uses their own systems.

At MB, the star diagnosis is 1 choice.
A little more expensive, but a good investment. Would miss it..... :-) :-) :-)


Best regards

Stenzel

MBNRG

Try Carly for Mercedes: https://www.mycarly.com/

I find it interrogates a very in-depth, comprehensive list of systems/subsystems, and was able to clear Fault Codes that only very few Non-dealership scanners costing many times more could clear.
They are a German company, with exceptional tech savvy to query and interpret many if not all the MB ECU systems.
Android and Apple compatible.

Acta_Non_Verba

Hi Andrew,

First, a few words how OBD system diagnostics is structured. All manufacturers use this system. There are four "systems" that fall under diagnostics definitions:

P-Codes = Powertrain
B-Codes = Body (security)
C-Codes = Chassis
U-Codes = Network (CANBUS protocol)

P-codes are the most universal and standard in that the same P0xxx code means the same in all cars. So, a P0303 is always a misfire, cylinder #3 in all cars. Some P1xxx codes are standardized, at least as manufacturers assigned these they stayed with the same definition if a P1xxx was already assigned. Then, from there (P2xxx, P3xxx, etc.) it gets really unique to a manufacturer. P-codes, by this definition, are intentionally made to be open but more primarily BC another name for powertrain codes is Emissions codes, and because governments have a vested interest here P-codes had to be defined as universal and open access is mandated. With that, any "scan tool" out there reads P-codes, some are better or fancier than others, but that is their primary function.

ALL the other categories (B, C, U, and the higher numbered Pcodes) are manufacturer specific, although, here too, once a code was established by one manufacturer another one would use that too for the same diagnostic so as not to have the same assignment mean different things. As an example, a U0101 means a TCM lost communications, across manufacturers. As these lists increased some number assignments went to a single manufacturer BC an exclusive feature is only used by that manufacturer.

P-codes produce a Check engine light (CEL). All other codes DO NOT, and are IDed through other means, some are fault lights on the dash (other than the check engine light) such as the ABS icon, SRS icon, or in written message in the communications center. Every manufacturer does this their way besides some very common icons.

Finally how code is written among manufacturers is NOT standardized, so an access tool (deep scan tool) had to become unique to that manufacturer. This is where manufacturers took advantage of creating their own system, their own diagnostic tools which, in a way, helps their repair networks with business as only their tools can read their codes. An interesting factoid = a modern car today averages about 100 million lines of code.

Bottom line - only specialized tools would have gotten you to any other faults that you have, the powertrain codes being the exception. Lately, however, some tools in the marketplace are able to cover specialized codes from different manufacturers and bundle these in single tools. They might not be 100% complete but they're getting better and better. I've played with a couple of these tools. One I've had for a couple of years now and so far it has worked well to deep scan all systems. It covers just about every manufacturer out there. I've tried it on four different manufacturers, my car and a couple other older MBs. It's an Autel MX808. It is reasonably priced, and not even the biggest tool they produce. It does have to be updated, and I am constantly getting new updates. I recently did a thread here when I had a complex CANBUS error. I used this tool to diagnose and it took me to where I had to go to fix the fault.

So, the question to you - How much do you want to access? If it is just powertrain faults (Check Engine Light), any $15 scan tool will work fine. If it's everything on this platform the goto is Xentry, or some tool like I am using. Here is an example of a deep scan I just did on my car a couple weeks ago and the modules it scanned.



Here is one of 7 screens of car manufacturers covered by the Autel tool.

AndrewFerg

Thanks, all! I'll report back with success / failure. I've had a "limp mode" event and I'd like to see the error code sooner than later and I don't want to deal with my local dealer if I can avoid them.

AndrewFerg

I love being "around" people who know more than me! Thanks for the lesson. That all makes great sense.

Dave Backmarker

I also use Carly. It works on my 2018 AMG GT S as well as my 2013 GLK350.

descartesfool

I bought an Autel MS906BT scanner programmer, and it works on every make and model of car I own. Comes with a Bluetooth rechargeable OBDII dongle, so no wires required at all. It was essential to use this to reset the engine oil minder in a Porsche Cayman 718, and of course shows all possible codes on my AMG GT-S. I never bought the subscription as the most modern car I have is a 2019. When I buy something newer, I will get a 1 year software upgrade. Unit costs a lot more than a plain OBDII scanner, but it does so much more. A very good mechanic friend of mine told me that is what most mechanics he knows now use the same or a very similar unit. New models from Autel are coming out regularly.