pcmhacking.net

I need help sending gm can commands
I have several things mapped out just need a way to send commands
I have a python script that works well for vpw
But trying to convert it to can not going so well

I think the error is in the at commands I don’t think I’m setting up either the header or rx /tx response filter correctly.

I’m using com port through elm327 I set to protocol 6 for can np
And if I send 00 00 7e0 plus 1A 90 it should send the vin
But when I print the response I get data na?

If I send can clutch learn command I can learn the clutch but I’m
Not seeing any response messages!

How to print the gosh darn response messages lol

This is all I use ...

AT Z
AT E1
AT L1
AT S0
AT AL
AT SP6
AT DP
. . ISO 15765-4 (CAN 11/500)
AT AR
AT AT0
AT H1
AT ST FF

Then just send 1a90.

This is what I use to set up my OBDLink MX for single wire operation. It's based on a STN1151 chip. A legit ELM327 should be similar.

ATL1
ATE1
STP 63 (SW CAN (ISO 15765, 11-bit Tx, 33.3kbps, DLC=8))
ATSH 00 02 4C
ATCRA 00 00 06 4C

Dual wire CAN would be STP 33 (HS CAN (ISO 15765, 11-bit Tx, 500kbps, DLC=8))

I don't know what the ELM protocol equivalents would be.

Elm is exactly the same will give this a try tomorrow

ATCRA 00 00 06 4C

Thats like the missing link

ELM is a hard one, there are probably no legit elms in the wild. But there are many versions, clones of different firmwares, different hacks, different bugs, different configurations, entirely different 'compatible' codebases with minor differences or some commands not implemented and different hardware both MCU, and on board outside of the ELM327 chip. What works on one ELM327 wont work another. You can definitely try what works for someone else but no guarantees. This is why they are not a good option for playing with this stuff, even if they are cheap and plentiful. If you want to spend time problem solving and save a few bucks, they can be OK.

Hiya antus and all,
is there a database of elm commands? I'm sure there is but I have been too lazy to look I like my little red usb cable for generic stuff. I've never logged much with it. If anyone has it or most of it handy, I'd like to look at it and the definitions. Thank You

Or if you want the latest full manual OBD to RS232 Interpreter


-Enjoy

Thanks:) no matter what I try this is the out come always says rNO DATA

('The cable model and version is', 'AT Z \r\r\rELM327 v1.5\r\r>')
('The repsonse from AT DP is', 'AT E1 \rOK\r\r>L1 \r?\r\r>S0 \r?\r\r>AL \r?\r\r>SP 6 \r?\r\r>DP \r?\r\r>')
('AT AT0', 'AT AR \rOK\r\r>AT AT0 \rOK\r\r>')
('The repsonse from AT CRA 00 00 06 41 is', 'AT H1\rOK\r\r>FC SH 00 00 01 01 FE 01 3E 00 00 00 00 00 \r?\r\r> FC SH 00 02 41 \r?\r\r>CRA 00 00 06 41 \r?\r\r>')
('The repsonse from 1A 90 is', '1A 90 \rNO DATA\r\r>')
('The repsonse from 1A 90 is', 'AT CRA 00 00 02 41 \rOK\r\r>90 \rNO DATA\r\r>')
>>>

If you break that down to it's individual elements you will see that there are multiple incorrect AT commands , they have no preceding AT, that is incorrect, each AT command must be proceeded with AT else it will be interpreted as an OBD message.

IMO you should be testing with something like PuTTY that is simple and clear.

Once you figure out the command sequence then use that to create/modify a script.

Just my opinion ... Take it or leave it as you will!

-Enjoy

The below settings worked for me but won't receive or send long enough messages the response is cut off? And python is not working correctly with these commands it doesn't print correctly.

example request for vin is cut off

>1A 90

7E810135A9031474350

msg should be much longer





putty
session settings:
Serial com4
speed 38400

Terminal :
deselect auto warap

select both implicit CR fields

open

type commands bellow

AT Z
AT E1
AT L1
AT S0
AT AL
AT SP6
AT DP
AT AR
AT AT0
AT H1
AT SH 00 07 E0
AT CRA 00 00 07 E8
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