For those of us in CA, starting 7/19/21, Your PCM will now be scanned for any "adjustments" and if found you fail.

From what I have read:

it seems that the easiest way to check for software changes could be through something called a CVN (Calibration Verification Number). The number is actually a checksum — something that the ECU adds up from each segment of memory. Basically, when you change software or coding, the sum of the numbers in the memory segments changes, which changes the total checksum. This makes it easy to spot mistakes or changes in text or code, and CARB will apparently use this as a known profile to check individual cars against, thanks to automakers submitting data or years of data collection via smog checks

PCM programming is above my pay grade so IDK if our 25 year old bricks have "CVN" or what "data" the smog **** has either collected or received from auto manufacturers. But if they are able to detect changes I suspect this will make it very difficult if not impossible for a "cooperative" (read $300 guy) smog shop to circumvent.

While I have several modifications requiring PCM adjustments, I have previously always passed smog test and that is the no favors full colonic kind (plug in, visual, tail pipe on rollers @ 15 & 25mph)

​​​​​​​Any PCM tuner guys have comments on how this works?

 

Scanning wise, probably OBDII stuff since they never did scan OBDI PCM for "not ready" codes and relied on sniffer results.

 

Yes this is for OBD2, 96 and newer cars.

Ironically even if a PCM change has nothing to do with tail pipe emissions IDK if "any" PCM change can trigger a problem causing fail

Its insane, if the "emissions" aka tail pipe, you know what actually puts pollutants in the air, test pass than it should not matter what is under the hood....but I digress

I know VW was the reason this all started along with diesel cars/trucks with tunes that spew black coal or the rice cars that do the over fuel to get the exhaust to pop shiat but this has many out here in pucker mode. Yeah the high $ Lambo, Ferrari, BMW whatever guys can likely just "restore" to a stock tune but for modified engines that would not run on a "stock" tune without triggering a Christmas tree of CEL's ...this is a problem

Ideally someone who "speaks PCM" can advise on what can be seen, if anything, by the plug in test they are now doing. Previously it was just IM and CEL check which for me was never a problem....but this new shiat will be a kill for many if in fact CVN is altered due to aftermarket tuning on these 25 year old bricks (PCM's)

 

Basically where I stand on the matter, too. If the person is being responsible in modifying their vehicle and meeting emissions at the tailpipe, then it really shouldn't matter what the PCM calibration is because the emission standard is met. Unfortunately, clowns have been running rampant for too long selling catless connection pipes with an "offroad only" disclaimer and a wink, and other fools have been buying them up and turning all the codes off for their daily transportation 15 second racecars. It was only a matter of time before the regulatory bodies caught on. I'm honestly surprised it took this long to happen.

 

so how does this work with all the CARB compliant stuff, like a supercharger... Obviously you have to put a tune it but doesn't that now mean most CARB cert'd stuff is useless? companies spent big bucks to get certified and now it is wasted?

Fortunately I am not in California so no worries, but seems we all pay higher prices for parts as I am sure we pitch in for the CARB stuff.. Good news for us out here in the semi free states maybe prices go down

 

I am just about to get a engine back from rebuild for a 911,, it comes with a tuner that can carry 5 tunes,, 1 is the original stock tune.. takes about 5 minutes to switch..
Oregon does a "plug in" emissions test, I plan on going through with the optimized tune and if it has issues, then I'll put the stock one back in.
Joke is the tune I'll be running is basically to modify some settings that have been found to damage the engine,, its actually a cleaner tune overall than the factory one.

We shall see.....


My swapped 5.3 jeep is running a antique vehicle plate.. > than 96 so I'm out of the testing zone for my area..

 

ANY CARB approved programming is OK but I suspect there will be a great many "false" fails.

IDK the specifics on how their software "see's" what is a problem other than what I have read is the assumed way is to check the CVN which will show a "checksum"...apparently a set measure in stock tune. I have to think this is going to be a cluster F where many legit tunes are flagged forcing one to see the "referee" and that is a brutal inspection you never want and those guys are programmed to fail anything.

GM "reprogrammed" my computer over 20 years ago to "disable" the air pump. Have the GM CARB sticker and TSB for it. Then I did a gear change....would either of those show fail because those changes change the "checksum", IDK. Beyond that I have a tune for larger injectors/TB/CAM, etc which I assume are the bigger problems

This is why I am asking the ?'s on here if any CA guys, especially ones who tune and know the core operating functions of these old PCM's. In todays ECU standards these are very primitive "bricks" and IDK if they even can show a "CVN" when scanned. Maybe its how the states computer just reads the file name. I have a sticker on my PCM from tuner with a "BIN" file #. If the program is titled that way than that will be a red flag if in fact they can read file name which I think is something they can do. Some tuners actually add "signature" or even some blocking codes so someone else can't see what they did. More to keep people from copying their stuff but my reading says those are the kinds of things that the State's software will be looking for. To me having a one size fits all OBD2 car companies coding is not realistic. Maybe they will target specific car makes, model, years...IDK.

 

Well boys & girls...there may be a break in this issue. "some" LT1 OBD1 & 2 PCM's do not show/have CVN#'s. To check if yours do go to this site and enter VIN and check the options which shows everything. My PCM does not show any CVN #'s so there is no "checksum" the smog **** can see

It does show, for my VIN, 3 reflash TSB #'s issued for my car and I had dealer do those back when and have the TSB;s for it and the CARB EO# for the air pump "disable" so that won't be a problem for me. Basically the state (CA) plug in to my car will be blind to see any "programming" changes other than what they have previously scanned for which are the IM (monitors) and for any CEL which has never been a problem for me.

tis2web.service.gm.com