Jump to content

Realdash connection using generic Elm327


Recommended Posts

Looking for some advice using a generic Elm 327 adapter for realdash.

I have been doing some fiddling trying to get Realdash working with a generic Elm327 adapter. Has anyone else tried this?

I read that it was not possible to use a generic Bluetooth adapter for Realdash, and you needed to have an OBDlink mx(+) to make it work. Or a CAN to usb adapter like the seeedstudio etc.

I thought I would give it a go with the generic adapter, and have had some success, but I dont think it is working 100%.


What I did to get it going was as follows:


Connect the can HI/low lines from can2 to a OBD port plug from ebay (along with power and ground obviously),

Plug in a generic OBD Elm327 adapter,

Changed the CAN2 setting in PClink to: OBD (ISO 15765 on CAN2),

Set Bit rate to 500Kb/s,

Update rate to 200hz,

Set mode to DASH2pro, ID 1000,


In realdash:  I (originally) tried to set up the adapter selecting "Link Ecu" - Bluetooth - Select correct Bluetooth adapter from the list. This did not work, and would not connect.

After some more trial and error I selected OBD from the list - Bluetooth - Select correct Bluetooth adapter from the list. This then was successful, and I was connected.

I then noticed that even though I was now successfully connected, non of the gauges were functioning, However, going into the input menu (of a particular gauge) and reselecting the already selected input (ie. reselecting Coolant temp for the ECT gauge, and just reselecting it as an input had the gauge come to life!)

(On a side note, one thing I noticed is that if you don't select "link ecu" and try and connect that way first, even though It will not connect, you will not have the Link specific inputs available when you connect using the OBD method, well at least I didnt from a fresh install of Realdash on android)

As I said earlier in my post, it is almost working properly, but not completely. I have most of the gauges I have tried working, including the following:





Boost (although working, I think the CAL is off somewhat, or the gauge I was using was wrong for the input),


and maybe 1 or 2 more I cant remember.

However, when I tried to set up oil pressure as an input, I just couldn't get it to work. Tried everything I could think of, until my brain started to hurt, I just dont know enough about this CAN thing, it is very confusing. I failed at getting the engine check light to work also.


I guess my question(s) are.... If I have managed to get so much going using a generic Bluetooth adapter, why is it not possible to have all the data transmitted this way? (is it a limit of the OBD protocol) And why is it said that is does not work, as it at least partially does? Obviously I have not got everything going that I wanted too (really wanted pressures etc) But I have quite a lot of the main info coming in. I am missing something as to why this is not a viable approach?

The data flow seems to be almost real time, with only a very slight delay. Ie, the rev counter tracks the revs with only a very small perceptible delay, and would be fine for most people in my opinion. If I could get all the gauges etc to work as well as the ones that are functioning do, I would be a happy camper.


All this was achieved without changing the XML file or the .rd file. To be honest I dont know where to start with those. I figure from my reading the XML file is uploaded when you select CAN/Lin adapter from Realdash (something I didnt do as I selected OBD instead) and I'm not sure what you do with the .rd file.


Im interested if anyone else has tried this, and If they have had any better results than me.

Id also like the hard word (if it is appropriate) to just go and purchase the OBDlink Mx+, because it would make life that much easier (for these reasons............... etc)

If I do buy the OBDlink mx+, and upload the premade XML and. rd file, are all the major data streams coming from the G4x already configured? So it would be as easy as say... creating a fuel pressure gauge, and selecting fuel pressure from the main input choices in RD? or do you still need to go into the ecu specific input menu and mess around in there?


Any help/ advice / or interest in what I have got going, would be greatly appreciated.  


Thanks in advance.



Link to comment
Share on other sites

Oil pressure is not in any of the common OBD2 standards, there is a fixed set of basic parameters (see: https://en.wikipedia.org/wiki/OBD-II_PIDs), the ones that Link supports are  listed in the help file page: G4+ ECU Tuning Functions > CAN > OBD (On Board Diagnostics). 

Generally for a driver display OBD2 is noticeably slow.  OBD2 is a request/response type communication - so for example the display has to first send a message to the ecu "please send me the current RPM", then the ECU responds with the current RPM (just one single value).  The display then has to again request "please send me the current RPM"...  and so on as often as it can.  It needs to wait until it gets a response before it can ask for any other channel.  It needs to ask for every single data point for every single PID that you want continuously over and over.  So the more channels you want, the slower it gets.  

So highly recommend the OBDLink MX+ or the usb adapter, the OBDLink doesnt use OBD2 - it uses raw CAN just like the USB adapter so you can send whatever data you like.  


Link to comment
Share on other sites

Thanks for the quick reply. Understood. Just wanted to confirm I wasn't a genius to get it going this way, lol. The OBDlink mx+ is quite expensive, but I guess you get what you pay for. Guess I will be saving my pennies. I think the Bluetooth adapter may be the better way to go, as I see people are having problems getting the wired solution to work alongside powering the device.


Thanks again for you quick reply, and the benefit you bring to the community.



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...