Software On ELM Street - OBD2 Software Development

[Jayme]

when the windows serial buffer was full.... I wasnt just losing packets, I was losing random parts of packets and having cut offs in places... was very odd..

[ejukated]

Ahh just connected... take about 5-10mins warmup before the tech2 recognizes it.
That has to be the most weirdest things it does.

Im amazed the elm is keeping up.. its logging ~305frames/s

Mines the same, turn it on, let it sit on the main screen for 5-10mins then turn it off and on again and it will say Candi detected and you're off... Havent worked out exactly what it is yet. If you have a spare I can take a look.

[Tazzi]

Yeah I think it starts overwriting previous bytes once its full.. or just doesnt know what to do with them?
Tried bumping up the buffer size in windows?.. I think the serialport control has a default size of 4096 or something like that.. maybe quadruple it? lol Im assuming that works.. why have that option if you cant modify it.
Shame they didnt do the same on the elm.. would have thought they would utilize any free ram for the serial buffer.

[Jayme]

yeah once I started reading the bytes from the windows serial buffer fast enough in my app, it stays empty... so I dont need it any bigger now

[Tazzi]

Mines the same, turn it on, let it sit on the main screen for 5-10mins then turn it off and on again and it will say Candi detected and you're off... Havent worked out exactly what it is yet. If you have a spare I can take a look.

Dont have a spare CANDI module. But at least you know its not just your unit that does it.
Since Im looking to get a spare VCI module.. might grab another CANDI module at the same time since there pretty cheap

[Tazzi]

yeah once I started reading the bytes from the windows serial buffer fast enough in my app, it stays empty... so I dont need it any bigger now

Let me know if you get it logging.
Or if you need any explanation on the "flow control" frames. Im just reading up on them for the ELM device


Iv got some interest in this BCM relink with PIM/ecm. But since the BCM is on ALDL.. I figure both ALDL and CAN are required at the same time here to capture whats going on? But.. the CANDI module is connected so it cant do anything over ALDL??.. eh duunnnooo. Might try capture something with the ecu unplugged first so I dont go killing it quicker. Unless some special communication directly between the PIM and ecu occur.. and only special commands to the ecu/pim are required?

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[Jayme]

I was under the impression that the PCM links to the PIM... I know if you swap PIM to another car... engine wont start.

[Holden202T]

maybe the pim and ecm connect via the bcm ?!?!

[Tazzi]

maybe the pim and ecm connect via the bcm ?!?!

I was under the impression that the PCM links to the PIM... I know if you swap PIM to another car... engine wont start.

In the holden documentation.. it goes ECU to PIM to everything else including BCM. From what it shows, the ECU has no direct connect with anything else.

So.. Id assume the ECU and PIM configure them selves first.. then the PIM would then communicate with the BCM and match up there... using the vin or security code or something.

Hence the when clicking the "unlock" on the key or trying to start the car.. the key sends the encoded security.. the bcm picks it up.. sends it to the PIM, and the PIM then sends it to the ecu. If the ecu doesnt respond with 4seconds of the code, then pim shuts off injectors (thats all from memory btw.. It might be slightly different but I read that a couple days ago in the docos.)

[Jayme]

how I understood it was the BCM gets the correct code from the keyfob, then sends it to the PIM, which sends it to the PCM. all 3 modules must have the same VIN programmed into them or it wont work... would be nice to understand how it works as replacing alloytec pcms is a bit of a voodoo process and nobody knows much about what to do and what works etc... many just end up finding a wreck and grabbing BCM PCM PIM key and putting the lot in haha.