Pontiac G8 Forum banner
1 - 15 of 15 Posts

·
Registered
09 G8 GT 427 LS3
Joined
·
272 Posts
Discussion Starter · #1 ·
California Won’t Let You Register Your Car if It’s Tuned
 

·
Premium Member
Joined
·
7,445 Posts
And the subsequent exodus continues.
 
  • Like
Reactions: d00by

·
Registered
Joined
·
54 Posts
I had to pass an OBD2 test on my 99TA when I had it.

Long Tubes/ no cats/ no rear 02's/ LS6 manifold w/ EGR delete

Frost did my tune(mail order) and enabled the monitors that they check for and I passed with ease.

I did a tail pipe test just for laughs as I used to work for this shop and the car failed miserably.

If you have a good tuner it shouldn't be a problem.

Besides Cali already does a visual inspection and I would have failed that if they did one here.
 

·
Registered
2009 MGM GT. In need of wider tires and LSA
Joined
·
61 Posts
Any info on how exactly CA determines that your ecu is modified?
 

·
Registered
Joined
·
2,401 Posts
They look at the cvn on the file and compare to what came from the factory. Any changes, ANY, alters the cvn. This includes something as simple as speedo adjustment for a different axle ratio.

Clip from efi live:
Q - What is a CVN?
A - CVN stands for "Calibration Verification Number", this is a fancy name for checksum. What the ECM (or TCM) does is add up all the numbers within each segment of the flash memory, the total of those numbers is what the CVN equals. This allows people with a TechII to quicky check the data in each segment is correct or unaltered (eg, the CVN matches a known program).
If any data is altered within the segment then the checksum (CVN) will change or not match what it originally was.
 
  • Like
Reactions: lastcall190

·
Registered
Joined
·
1,759 Posts
It’s really addressing a very small % of the total number of cars. It will cost way more to test every car to catch a few offenders. In Wa state, they have eliminated testing all together. So I don’t see it happening up here. But if it does, I’m in trouble because my stock tune won’t run my cammed LS3 and my high flow cats don’t do ****! Haha
 

·
Registered
Joined
·
358 Posts
If any data is altered within the segment then the checksum (CVN) will change or not match what it originally was.
Thanks for that explanation. So what if something is altered, then changed BACK to a factory calibration? Will that re-flashed factory calibration still produce a non-OEM CVN?
 

·
Premium Member
Joined
·
7,445 Posts
Why not get a second ECM flashed with your VIN and stock program?
Not quite that simple since typically a tune is performed to support various modifications i.e. aftermarket adjustments made to the vehicle. If the factory tune were adequate after the changes, it would negate a re-tune since stock is a tune. Simply put, the old tune settings are incompatible with the new parts just like the new tune settings are incompatible with the stock parts. Hence the term back to stock i.e. removing the bulk if not all aftermarket modifications and returning the tune to factory specifications.
 

·
Registered
Joined
·
2,401 Posts
Thanks for that explanation. So what if something is altered, then changed BACK to a factory calibration? Will that re-flashed factory calibration still produce a non-OEM CVN?
The first step in changing a calibration is to pull the original and store it. The CVNs would be OEM. This file can be loaded back in as needed. It's still unlikely to pass as the car will need to have all the emission tests passed, in ready state that requires a drive cycle. Mechanical changes to the car that drove the need for a tune will not pass all the emission test or will throw a CEL.

Bottom line is - sell the car.
 

·
Registered
Joined
·
136 Posts
The first step in changing a calibration is to pull the original and store it. The CVNs would be OEM. This file can be loaded back in as needed. It's still unlikely to pass as the car will need to have all the emission tests passed, in ready state that requires a drive cycle. Mechanical changes to the car that drove the need for a tune will not pass all the emission test or will throw a CEL.

Bottom line is - sell the car.
Keep the car, sell California to Mexico. Problem solved.


Sent from my iPhone using Tapatalk Pro
 

·
Premium Member
Joined
·
4,810 Posts

·
Registered
Joined
·
4,732 Posts
Can the software to write to the pcm creat your own CVN. Make it match the original?
 

·
Registered
Joined
·
54 Posts
Not quite that simple since typically a tune is performed to support various modifications i.e. aftermarket adjustments made to the vehicle. If the factory tune were adequate after the changes, it would negate a re-tune since stock is a tune. Simply put, the old tune settings are incompatible with the new parts just like the new tune settings are incompatible with the stock parts. Hence the term back to stock i.e. removing the bulk if not all aftermarket modifications and returning the tune to factory specifications.
Yes I realize that if its cammed the car will not run right but if its just tuned for bolt ons it would work.

Your not passing smog with a cam or long tubes in southern Cali anyway .
 
1 - 15 of 15 Posts
Top