Hi all, my 1st post here, so be gentle.

I have a 1999 Volvo V70XC B5254T  Automatic that I'm trying to disable some DTCs.

It is more for fun than anything else.

I got the FLASH out of it in boot mode and was going through it for a few days trying to find DTC Class Table. Unfortunately, I did not succeed. I found the probable location of CARB P-codes (16 bits values) and the DTCs in it but cannot for the life of me find the class table to see if I can disable some codes  . I found similar file with corresponding al2 file but the location of the class table is in different location in my file. In my file I found corresponding a2l file, 10R1HJ.a2l but could not find it anywhere.

Maybe someone got better understanding or wants to try to see if we can figure this thing out and learn something along the way.

I attach all related stuff and the file in a attachment.

https://mega.co.nz/#!vwlVBKba!sxlHYspSIrlJsvGC8P_Zdq5V_-J82ndgjG2K0rl_GQE

Thanks in advance  .

Roth

select full link, copy, paste.  It works.

Thanks for answering.

BTW, I noticed that I posted in the noob Guides and FAQs instead of questions. Maybe mods can fix that, thanks.

Here is the closest bin with matching a2l I could find.

https://mega.co.nz/#!n1sRgDjL!ueW4FXR8IduJNhM32aH8GEQVwqkznQx__QU5lBTE2r0

0.0Vatlab VOLVO ID.  99W20 P80 B52X4XT ME 7.0 1XEB    F1EBI P80 B5234HT MAN SDB259 EU ŽT9920 981028 02:29 B6EB           1XEB0000    4C2A                                                    

0.0Vatlab VOLVO NO.Jens Ivarsson           96551           +46 31 7651395  DAT3012         1xEbMHde.a2l    981023 12:07

I can see the class table beginning at 0xD886 (in the a2l) which seems to correspond with the file and there is some DTCs I found around 0x149xx, which does not correspond to a2l file that says they should be at 0x14Exx.

This I found based on misfire codes and BTW I found out that the file contains codes for 8 cylinders (even though the engine is 5 cylinder). They look like this, starting at 0x1493A:

0300 0300 0300 0300 0301 0301 0301 0301 0302 0302 0302 0302 0304 0304 0304 0304
0305 0305 0305 0305 0303 0303 0303 0303 0306 0306 0306 0306 0307 0307 0307 0307
0308 0308 0308 0308 0300 0300 0300 0300 0301 0301 0301 0301 0302 0302 0302 0302
0304 0304 0304 0304 0305 0305 0305 0305 0303 0303 0303 0303 0306 0306 0306 0306
0307 0307 0307 0307 0308 0308 0308 0308

So if this is a five cylinder motor, the class table should have corresponding pattern of last 3 codes (cyl 6, 7 ,8) inactive. The only codes then would be P0300 / P0301 / P0302 / P0303 / P0304 / P0305 giving me pattern of:

active active active active active active inactive inactive inactive.

In the file it is 27 27 27 27 27 27 00 00 00, starting at 0xD88C which by the al2 is the P0300 code.

I tried to find this pattern ( xx xx xx xx xx xx 00 00 00 ) in my file as it also is 5 cyl engine but no luck.

Maybe someone has some other idea on locating this table or maybe there is some other method used in this case.

Thanks again Roth.

Thanks, yes, I tried to look for 00 00 00 proceeded by 6 of the same bytes. Next thing I thought of is to work trough as many files with matching a2ls to discover maybe a different method / location of DTC de/activation.

roth

I run out of time on this. I just filled DTC Class Table with 00 and wrote checksumed file back. Car is starting and running now running now. Let see what happens. Checksumed / modded file attached if anyone cares to look.

BR, Roth.

He's disabling all DTC's to prove a point that he has the right table, he's not just doing it for funsies.

So line up the DTC table in groups of 4, count the total amount of rows.
Then take the fault class table in 8 bit, it has the same length as there are 4 value rows in the pcode table.
Take the number of the row which contains your DTC to be disabled, and count the same amount of 8 bit values from the start of the fault class table, set it to zero.

At least VAG works that way, I haven't looked at Volvo.