Software On ELM Street - OBD2 Software Development

[Holden202T]

ok I tried this in the VZ, got the elm installed then selected com port, speed and auto, then tried to connect, retried a few times then failed saying no elm device detected....

question is, is this an issue of the software not seeing the elm or not seeing the car ?

I dunno what drivers its supposed to use so got CP2102 drivers off the net after a search and it seemed to install correctly ?

[antus]

i'll be different for different clones. the one i have in front of me has a pl2023 chip which is a different brand of serial->usb. CP2012 is likely correct for yours though, they are cheap and common, too.

[Tazzi]

ok I tried this in the VZ, got the elm installed then selected com port, speed and auto, then tried to connect, retried a few times then failed saying no elm device detected....

question is, is this an issue of the software not seeing the elm or not seeing the car ?

I dunno what drivers its supposed to use so got CP2102 drivers off the net after a search and it seemed to install correctly ?

So the "No elm device detected" is when the elm device doesnt respond back to "ATZ", which makes the ELM send "ELM VX.XX" where the x.xx is the version number. It may be a drivers issue? Since it definitely responded back on other ELMS.

Holden202, could you install that serial port monitor (its free!), run that then run my software and see whats actually happening?
If the serialport monitor doesnt show a response from the elm.. then it elm isnt responding.

What baud rate did you try? Maybe try other rates?


The code I have there is:

Code: Select all

SerialPort1.WriteLine(ResetDeviceFrame) 'Sends ATZ
            CheckResponse = DetectElmDeviceGetResponse(ResetDeviceFrame, RichTextBoxConnectionActionLog) 'get response and check
If CheckResponse = "Failed" Or CheckResponse = "" Then
                SetRichTextBox_ThreadSafe("ELM Device Not Detected!", RichTextBoxConnectionActionLog)
                MessageBox.Show("ELM Device Not Detected!!", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Error)
                Exit Sub
ElseIf CheckResponse.Contains("ELM") Then 'if elm device, display info
                SetRichTextBox_ThreadSafe("ELM Device Successfully Found!", RichTextBoxConnectionActionLog)
                SetLabel_ThreadSafe("Device: " & CheckResponse, LabelDevice)
End If

So basically, it checks if the response contains "ELM", if so that it got the response!. If the elm doesnt respond back, the software will timeout and send back a "Failed" message.

[Tazzi]

Just ran it on the elm simulator. Ran through it all happily with a set protocol (Eg VPW)... when set to auto protocol, that requires connection with car to determine cars protocol.
As long as the device is actually powered up correctly, and on the correct baud rate for communication. Should happily connect up.

[delcowizzid]

i can only detect my elm when powered on the bench doesnt work plugged into car that was a few versions back now LOL

[Tazzi]

Yeah... thats weird.. hence why we need to have the serialport monitor running to see whats actually being sent between the elm and software when in car. I dont get how it can work on bench but not in car! Weird!

[Holden202T]

yeah i did try different baud rates to see if that made a difference and also tried to select can protocal ..... will have a play with the port monitor when i get some time.

so you guys are saying if i plug the elm in to the laptop but not the car and the drivers are right, i should be able to hit connect and it will respond that its found the elm ?

[Charlescrown]

Mine must be plugged into the car with ignition on then it connects to elm.

[delcowizzid]

yeah i did try different baud rates to see if that made a difference and also tried to select can protocal ..... will have a play with the port monitor when i get some time.

so you guys are saying if i plug the elm in to the laptop but not the car and the drivers are right, i should be able to hit connect and it will respond that its found the elm ?

i had to pwer my elm from my bench supply to detect it

[Holden202T]

ok cool, i did have it in the car when testing so that shouldn't have been the issue, probably driver related.

i have a LS1 pcm bench so i can probably test with that too till i can get it working.