Been like that here in MD. I have passed every time, no SES lights, no flag to the scanner. So many diff variables for it to go through on each car. Hell my truck flat out burns your eyes when it is idling in the booth, they come back smile, say you passed.

 

They have to submit a modified vehicle for testing to get the C.A.R.B. approval. It's very costly. They can't be responsible for what you do with it after the fact.

The smog program is after the engine side of things any way. Who is to say you didn't get a used ECU with a different calibration in it??? I wouldn't worry about the trans side of things. It's not like they climb under there to make sure you even have the correct transmission any way.

 

What they look for (in AK and in OR, not familiar with other states), is they check for DTC's, and make sure DTC's haven't been recently erased by checking the readiness moniters. This could be a problem for a speed density tune, since you have to fail the MAF sensor and set the code. But otherwise you should be okay if it's tuned properly.

 

Currently California has a sniffer test on the Dyno were applicable at 15 MPH and 25 MPH. If your AWD or to large for the Dyno they give you a static load test at 1500 and 2500 RPM with the tail pipe sniffer. Then there is a visual verification of all smog equipment and to make sure nothing is vented into the atmosphere. The Gas cap is also tested.

On 1995 and older they test the fuel system for vapor leaks with a pressure testing machine using nitrogen gas I believe.

On OBD2 equipped cars, they plug in during the test to make sure there is no active codes and that the monitors are complete. Your only allowed 1 not ready on 2000 and newer and 2 not ready on 1999 and older. On older cars it's a visual check for the check engine light function and to verify that it is not currently on for any reason.

 

What is a "not ready"?

I have disabled certain DTC's in the tune (six of them for the transmission to be exact because of the T56 swap), are these not ready's?

 

You can run the readiness test in EFI live. If it's all good then you'll pass the real thing.

Also, just so you know, my truck would not pass some of the readiness tests with a 2002 operating system and 4l80e segment swap. When I went back to the 2000 operating system and 4l60e segment it was fine. I could never explain that.

 

The On Board Diagnostic system monitors the engine values through various sensors as it's running to make sure everything is in check according to the vehicle's programming. The monitors run certain test and check it against known values that have to fall within a range while the vehicle is on and running under certain conditions.

The monitors report a pass or fail with a Ready, Not Ready, or Not applicable state to the rest of the system. If they detect a problem and fail they set off the MIL Malfunction Indicator Light. This is also referred to as the CEL Check Enging Light.

So when you go in for a smog Check the station is looking to see if they test have passed and completed. Some test will set right away while others have specific conditions in which they will run. Some times you have to drive at a certain speed for a specified distance while the engine is fully warmed up. Other systems need out side temperatures to fall within a certain range for the test to run.

I probably made it sound more complicated then it really is. Read up on readiness monitors and OBD2 testing for a better understanding.