CA/LA Smog

[oceansize]

The e46 may be exempt. Manufacturers were not required to submit CAL ID and CVN info for 2007 and prior years.

Page 6 of http://ww2.arb.ca.gov/sites/default/...og/msc0623.pdf

This would be the best possible outcome for all my e46 m3 holmies in CA. This little blurb says model year 2000 and later. https://www.bar.ca.gov/ARSC/Newslett..._Modifications

[heinzboehmer]

The checksum value is stored in the DME memory. The DME then recalculates this checksum based on what's in the rest of memory and if the two values don't match then the car won't work.

So potentially, if the smog computers are just reading the checksum value out of memory, you might be able to fool them by storing a "stock" checksum. Would require some program changes to disable the checksum check on the DME itself though, as the stored and calculated values would differ.

[skristedja]

This would be the best possible outcome for all my e46 m3 holmies in CA. This little blurb says model year 2000 and later. https://www.bar.ca.gov/ARSC/Newslett..._Modifications

beginning July 2020, BAR will implement Cal ID and CVN checks for most model-year 2000 and newer vehicles as part of the On-Board Diagnostic Smog Check inspection failure criteria

IDK how the CVN check would do anything without the manufacturer data to check against

[oceansize]

IDK how the CVN check would do anything without the manufacturer data to check against

Supposedly they have a database. Quote from the one PDF below. It is all over the map though in terms of what years it starts. On the EVO forums they said 2006. On that CA BAR website I found 2000. Another PDF says 2008.

"Section (g)(4.7.4) of the OBD II regulation requires manufacturers to submit CAL ID and CVN information. A template titled “CAL ID and CVN Data” is provided in this Mail-Out as Attachment E. For 2008 and subsequent model years, manufacturers are required to use the Microsoft Excel electronic template provided on the ARB website http://www.arb.ca.gov/msprog/obdprog/obdprog.htm for reporting and electronically submitting CAL ID and CVN data to ARB. For the electronic submittal, manufacturers may email the data to ARB staff"

EVO forum thread discussing people actually hitting this issue:

https://www.evolutionm.net/forums/ge...se-help-2.html

Data collection forms for CAL ID and CVN for manufacturers:

https://ww2.arb.ca.gov/resources/doc.../obd-resources

[T-Rex]

This new insanity is all the motivation I needed to finally start an LLC in another state...

CA really loves making our lives as miserable as possible

[terra]

terra do you know if the CVN is a calculated value or stored value?

It's calculated. Exactly how it's calculated isn't entirely clear to me. IIRC @gpetersen found that if you brute force the checksum such that the calculated checksum is equal to the stock value, then the CVN is also correct. So it's either itself a CRC16 (of each half) with a different initial value and/or polynomial, or it's some sort of calculation that's done to the calculated checksum.

Probably wouldn't be crazy difficult to hardcode the program to return a valid value

[shibui]

Goddamn this is some bullshit Sacramento

[sev]

i better get my smog in before the 19th. sad too i dont have a tune. i just have a few tweaks

[ridebikes]

I just want to chime in to say thank you to all who posted here, and especially oceansize for that Evo forum link: https://www.evolutionm.net/forums/ge...se-help-2.html

Between reading both threads, I just cancelled a big round of upgrades. It's just not worth it anymore

It's a shame that most of these modified cars likely sniff as clean as any stock car, but the original intent behind all the laws has been so completely perverted to basically destroy the aftermarket tuning industry in CA. Sad.

[Samsonite79]

It's calculated. Exactly how it's calculated isn't entirely clear to me. IIRC @gpetersen found that if you brute force the checksum such that the calculated checksum is equal to the stock value, then the CVN is also correct. So it's either itself a CRC16 (of each half) with a different initial value and/or polynomial, or it's some sort of calculation that's done to the calculated checksum.

Probably wouldn't be crazy difficult to hardcode the program to return a valid value

Maybe it's time for us to start a database/chart of what HW belongs to which SW, CAL, CVN so that we can reference back in case we do return to stock or "unmodified" software. This way, we can get an idea if we got the correct MODE 9 data for the california tree huggers... lol

So far I know this is real and true, which is for my MSS54 (non-hp):

for version 211322002801J469

SW ID: 7842975
CVN: 59D512B9

Cali ID: 7842974
CVN: 7DCC4B79

Program & CVN # can be found on https://nam3forum.com/forums/forum/s...me-information
but not the calibration/tune CVN#.

[sev]

Just got back from the smog place i usually go to. he said its going to get crazy starting monday. He showed me part of the new process he has to follow. Part of it involved reading the emissions sticker under the hood, which has the Test group number and the evaporative emissions family code written. He has to enter that into the system.

He also said theyre super going to be cracking down on looking for aftermarket cats or non CARB approved cats.

Obviously I passed this time.

[thegenius46m]

It's calculated. Exactly how it's calculated isn't entirely clear to me. IIRC @gpetersen found that if you brute force the checksum such that the calculated checksum is equal to the stock value, then the CVN is also correct. So it's either itself a CRC16 (of each half) with a different initial value and/or polynomial, or it's some sort of calculation that's done to the calculated checksum.

Probably wouldn't be crazy difficult to hardcode the program to return a valid value

If we can disable CRC check and modify the CVN and Cal ID to that of virgin stock tune parameters, this will be easy to bypass by spoofing. I'm thinking just mirror all these checksum parameters in the tune file (pic below) from the reference tables in the mss54 master page to match a virgin tune then just roll up lol. If its possible this will create some insane demand. Think of all the manual swap cars on hacked tunes.

Only other option is to do what repoman suggested which would be to modify unused sections of the tune to adjust the checksum calculation to match the virgin cvn number.

[Tbonem3]

Just got back from the smog place i usually go to. he said its going to get crazy starting monday. He showed me part of the new process he has to follow. Part of it involved reading the emissions sticker under the hood, which has the Test group number and the evaporative emissions family code written. He has to enter that into the system.

He also said theyre super going to be cracking down on looking for aftermarket cats or non CARB approved cats.

Obviously I passed this time.

Did he say what years, any cut off?

[siamkazi]

Did he say what years, any cut off?

This is the million dollar question....fingers crossed.

[jet_dogg]

Sevan, ask your boy if there's any mention of year cutoffs specifically mentioned.