Reverse engineering suzuki serial data line

[thatdevsherry]

Good update.

I got my simulator to work with the expensive AUTEL scanner!

Now I could sit down and program it to increment each value from 0-255 each couple of seconds and record the scanner value, but that would've been really time consuming.

Instead I took readings of each parameter at certain positions (0, 12.5, 25, 50, 62.5, 75, 100) %

Also went over each bit change in fault codes to find out which raw value corresponds to which DTC.

I'll go over these (AI helps a lot with formulas given the raw to processed values) and fine tune parameters like RPM, inj. pulse width since they're the ones that have 2 (high and low) bytes and the calculation is a little weird.

But happy that my simulator was finally able to communicate with the expensive scanner.

[fahdaliansari]

ive been looking to do this for my 2009 swift. i have seen rhinomans forum and the hardware part is just a converter for usb. was stuck on the what parameters to send.

[thatdevsherry]

Swift 2009 has SDL?

I thought it should have SDL/KWP. Have you seen which pins are present in the obd connector? If you can share that we can confirm if it has SDL, SDL/KWP etc.

SZ viewer works with SDL/KWP since this protocol is built upon the open KWP2000 which is supported by ELM327.

[fahdaliansari]

yea u were right. it does have SDL/KWP.

I still couldnt get it work with my elm327 and sz viewer. it showed wrong elm37 answer.
the elm327 is a clone version btw. Another thing is that my swift is the diesel version with the fiat mjd engine.

[thatdevsherry]

Ah that clears up things. SZ Viewer won't work since the ECU would be non-suzuki.

Here's a snippet from SZ Viewer.

EDIT: I may have read it incorrectly. Either SZ viewer "now" has basic support for non-suzuki engines or that it doesn't support it very well.

You seem to have pin 7 populared but also canbus (pin 6 and 14) so there's that.

[thatdevsherry]

Building an android app so I can plug my phone in and log/see data. Main reason is so it can also work with an android head unit connected to obd port through the vag kkl cable permanently.

P.S. this is simulated data in screenshot, but I've been able to get it to work well with my car too.

[fahdaliansari]

sz viewer show can bus not found and tries kline 5 baud. i have a magneti marelli ecu. u think that uses different protocol? or is my elm327 bad?

[thatdevsherry]

I'm not sure what your ecu uses. Seems like it should work with normal scanner apps over KWP2000 or CAN since it's not suzuki related. But I don't have any knowledge about the ecu or the protocol.

[thatdevsherry]

Open-sourced the prototype I had made for this. Once the mobile version is in working state I'll have that up on github too.

[thatdevsherry]

Managed to get live data on my cheap stereo display. Kinda excited it worked. It's quite a hacky setup. Fun nevertheless.

[phl.crombach]

Very interesting.
I have a 2004 Suzuki Grand Vitara with the same issue (Live on Aruba, car is 'Africa spec' so no O2,MAP and EGR.
Have an issue with my IAC not working. After swapping in a new one it seams that the issue is with the signal and not with the IAC itself, hoped to identify via OBD but ran into the SDL problem.
pins 2,4,5,9 and 16 are occupied on my OBD so that sounds exactly the same as your Baleno.
Will keep track of this topic to see if you find a way to get into the ECU.

If you have any tips on the IAC issue or how I could determine if that is the issue (with basic tools and a basic multimeter) let me know.
Keep up the good work

[thatdevsherry]

Thank you. Seeing the post really late.

I had figured out how to read data for my car (the addresses to query might be different for your car).

For quick fix you could use a scanner if a workshop has one. It shows ISC flow duty and you can run actuation test to see if you're able to adjust IAC valve. If rpm changes with adjustment then IAC is working.

The actuation lets you change rpm from 500 to 2000, so you can test if your ecu is able to adjust rpm to desired value using iac.

original prototype: github.com/thatdevsherry/suzuki_sdl

in-car scanner: github.com/thatdevsherry/suzui-rs