Software On ELM Street - OBD2 Software Development

[Tazzi]

After a couple hours, I think Iv sourced out a nice.. loooonnnng list of fault codes for GM... through programmically filtering through searches and documents
Should hopefully have all the codes for LS1 pcm, and most generic GM fault codes.
And any that we dont know, Ill run through the tech2 and get the answer.

[VX L67 Getrag]

I haven't actually found anything on my test bench on 29bit & have tested E38, E55, E69 & E77 & obviously all the older vehicles!

[Tazzi]

I haven't actually found anything on my test bench on 29bit & have tested E38, E55, E69 & E77 & obviously all the older vehicles!

Ah ok, thats interesting.. must be on VE's and up that use both 29bit and 11bit. And the infamous single wire gmlan (sw can).
If you get a free chance, logging the "clear faults" on a ls1 pcm and a vz v6 pcm would be fantastic! Just pulled the tech2 out to try and its being..stubborn..the connector is very temperamental.. and probably needs a complete replacement and resolder of the serial connector. Trying to position it in just the right spot so it starts working again

Will have to source out a new vci module for the tech2 otherwise!

[VX L67 Getrag]

Not sure what you mean about "clear faults" guessing not connected to an actual car?

But from when I tested the E69 & E77 they don't detect 29 bit CAN & they are both the VE V6 controllers & the E38 is the VE V8 controller so not sure what uses 29bit, can only assume possibly cars -F-ound -On- -R-ubbish -D-umps?

[Tazzi]

You know, click the little button saying "clear engine faults" on the scantool. Like this in the tech2 (old image):


Ah ok, well maybe the pcm doesnt communciate over 29bit on VE's, but other modules certainly do as the boys at carmodder have threads showing it.

[mattyc]

sorry been busy these are the exact wires the E55 VZ ecm needs;
Pin B3 - Pink - Ignition
Pin B23 - Brown/Black - Can Hi
Pin B25 - Black/Yellow - Fuel Level Sensor for Ground
Pin B36 - Orange/Black - Batt Supply Voltage
Pin B55 - Brown - Can Lo

Allways wondered about the ground wire, I have a clip onto the body of the ecu for mine, works perfect

Bench harness

image.jpg (786.51 KiB) Viewed 4174 times

[Tazzi]

Looks good Matty! Will have to look into making something similar!

[Tazzi]

Fault section is now re-modeled. No internet connection required or pop ups for view fault codes. All (Most) fault codes should be defined now!

faultsupdate.PNG (12.25 KiB) Viewed 4153 times

And also a little bit of custom reverse engineering abilities.. for those who are daring.. (Still finishing off)
Can be used to mimic a pcm, send custom data depending on a specific frame ect, the applications are endless.

Devwork.PNG (26.88 KiB) Viewed 4153 times

*To-do List
-Move all "action logs" into a central terminal app to make room for more items in each tab. So all updates/errors can be seen there.
-Automate all header changes, remove custom header in setup tab and add header section in custom frames tab
-Automate protocol detection/selection (use elm instruction AT TP)
-Apply PID setup/definition/selection so only wanted pids are displayed. Or split pids in different sections. Add different gauges/displays
-Add live engine data recording/replay. *Maybe* 2d/3d graph displays of logs.
-And finally, get 11bit and 29bit protocols working (VPW had been hardcoded to only be supported for all section except "monitor all")
-*not so important* reskin app.

[Tazzi]

Cant seem to get the VZ v6 units up and running. Iv got a harness and all.. but cant see any communication.

*Edit

Yep.. double,triple and quadruple checked the connections. Tried with and without the harness.. and still nothing. I have a few units to play with.. but none are outputting anything.

*Edit 2
Looks like I must have one of the infamous VZ ecu's.. which crap out and dont work! Got it working on the second vz v6 ecu.. on CAN 11bit 500kb/s. Also note, trying 250kb/s works.. but spits out incorrect data and a bunch of CAN ERROR messages

[Tazzi]

Looks like I have no choice but to get the Tech2 working again and connect up the CANDI module to start listening in on this CAN stuff. Havnt figured out how to get the vin or gm specific pids yet.. but all shall be revealed with the tech2 I would assume.

Iv watched a fair few programs now, to see what they all do. And they seem to only pull very "generic" info. The closest I found to a GM ecm was a pontiac gto 06 6.0L LS2.. which communicates over CAN 11 bit 500kb/s but none of the requests frames worked on the VZ v6 unfortunately.


Im hoping most info from the tech2 will be easily reverse engineered.. but, if the elm327 cable struggles to keep up, then its almost guaranteed that attempting to "mimic" the pcm chatter to the tech2 will fail using the elm. I will need to look into developing custom CAN board so the logging can take place on board and not be bottle necked by the serial port.
Wouldnt be such a bad idea either so this "buffer full" rubbish can be completely eliminated for R&D work.