Mode 8 Silence

[RobertISaar]

From other thread

my XDF was based off of Darren Freed's disassembly of a BSBH file. i added in a few things i found, but largely the MAF masks confuse me.

Thread split to this... EDIT EagleMark

there's at least a few reasons why 2E can act funny with datastream errors, especially if you have other modules in the car that communicate on the ALDL pin M circuit. HVAC/DIC/DIS/IPC/EBCM...

[EagleMark]

I've been learning that WHILE YOU HAVE BEEN ON VACATION!!!

and SIR... CCM...

When you catch up to the internet I'd like to find out if we could do Mode 8 for all known address then ask for data? Or does it have to be specific for only the extra module on line per car?

[RobertISaar]

i thought vacation was supposed to be fun? :D

anyways, you COULD send mode 8 commands to all 255 possible modules on the data line, but that would take quite a while to impliment into an ADX, let alone send over the ALDL circuit every time you log...

i think it would be better just to figure out which module is causing it by removing it's connection to the M pin, at least temporarily.

assuming it's not the PCM itself....

[EagleMark]

255?

Rbob was saying 15? I have only found about 5. I was trying to find them on my Buick LT1 and finding and disconnecting was way more time as they are not near ALDL port, but buried in line somewhere between ALDL port and PCM. Then looking through ALDL files then I found the issue with Buick LT1 was HVAC! Found it in manual in wiring diagrams! Not listed in ALDL file to write data adx but then found ALDL file for HVAC/SIR/EBCM which gave address. I still have not got it perfect, connect and data no good, disconnect and reconnect and data good on Buick, Chevy and Corvette, all same takes 2 connections for solid data so I am missing something. But I have got a few working while you were NOT on vacation...

Guess it'll take some testing to see if you send silence to something not there if it ruins the reply or connection...

[RobertISaar]

in theory, up to 255 modules can share the same ALDL line, but obviously GM never did that.

15 sounds a little on the low side of all possible ID's across all platforms/powertrains/etc, but it's a believable number.

[EagleMark]

But we are only talking about cars till 1995 too and that particular one was an F0 poll? 0xF0 not 0xF4...

HVAC I found was 0xEA and I think I just found my mistake!!!

[historystamp]

Here is a list of "all" non-engine data streams. I count 98 of them.

Robert

[EagleMark]

Man your getting good with the ALDL charts.

Now we need to figure which is complete seperate module read on other than Pin M of ALDL port. Only ones we need a Mode 8 silence for are ones tied to Pin M ALDL Port!

[RobertISaar]

alldata shows a 94 CS as having these possible things at the ALDL port:

radio
HVAC
ABS
PCM
Airbag

the radio and HVAC are connected to pin J
the ABS is connected to pin K

HVAC, ABS, PCM and Airbags are connected to pin M

notice, certain modules are connected to more than one pin.