Shall my app receive fault codes from a car through bluetooth?

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Ggaayi Abraham

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Apr 4, 2019, 8:28:23 AM4/4/19
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Hello guys...
I am designing an app that reads fault codes from the Electronic Control Unit through using a Bluetooth vehicle interface. 
Unfortunately, the app is unable to receive fault codes but it shows device is connected to the Bluetooth interface.
Attached is the picture of the blocks I setup. 
Please help!!
Abraham, Uganda.
mit app.PNG

Chris Ward

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Apr 4, 2019, 10:33:51 AM4/4/19
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Hi Ggaayi

Can you post details of the "Bluetooth vehicle interface". Minimum we need to know is the manufacturer, model, part number and exact Bluetooth version.

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hamil cooper

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Apr 4, 2019, 10:39:21 AM4/4/19
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I did not see in your pic where you sent a request code. To get the RPM, for example, you have to send 01 0C.

On my OBD module, all of the data is in Ascii.

After a connection, what I do is to send 01 0C and then get the response as you are doing.

TimAI2

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Apr 4, 2019, 11:56:27 AM4/4/19
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ABG

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Apr 4, 2019, 3:03:30 PM4/4/19
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@TimeAI2,
That's the best manual I have read in years!

It is both descriptive and prescriptive.

Special page to note: page 31,
about automatic text to hex detection and conversion.

Also, note that the AI2 code for Carriage Return is \r

ABG


TimAI2

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Apr 4, 2019, 6:38:48 PM4/4/19
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and probably just as useful:

Chris Ward

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Apr 4, 2019, 7:08:31 PM4/4/19
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...and probably already referenced in the other posts :)

ABG

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Apr 5, 2019, 10:35:38 AM4/5/19
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From what I see in the ELM327 manual, the first thing you should send
might be 'AT z\r' (see attached.0

Does that get you a response?

ABg



mit app.png

TimAI2

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Apr 5, 2019, 11:10:42 AM4/5/19
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I have been having a play with this effort in the gallery:


and have anglicised, remixed it and simplified (no output conversion)
Will save all output to a text file on sdcard for later review


Tested on a Mazda and it works and gives correct results when doing the conversions by hand

Gives a useful example of how to connect and send commands

Example output:
+CONNECTING<<80:01:84:9A:F3:78
?

>NECTED
?

>ATZ
010C
41 0C 0E 82 

>0105
41 05 5A 

>01 0B
41 0B 1A 

>01 10
41 10 00 F4 

>01 13
41 13 03 

>01 20
41 20 80 15 B0 11 

>01 40
41 40 FA D0 00 00 

>


OBDIIAI2.aia

ABG

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Apr 5, 2019, 11:23:02 AM4/5/19
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