How did they check for pending codes if they did not use a code scanner? You can't pass with more than two pending codes (one on some years).
That shop would be shut down by the state if it was found that they were passing cars without checking for pending codes.
That was the big problem in California. A significant number of out-of-compliance vehicles were causing most of the pollution. Even though percentage-wise the number of such vehicles was small, in absolute numbers it was large enough to cause a problem.
The "catalytic converter test pipe" was popular for a while. But as you said, in most cases, all the tampering with emissions controls did not have any effect on mileage and/or power.
They look for the light on the dashboard that indicates codes have been logged.
In some places they always use the scanner to make sure, for instance, that the ECU wasn't reset immdiately before taking the car in for inspection. In some places they do not.
--scott
Why people would not remove the "bypoass boxes" to return the vehicle to stock before submitting for E-Test is beyond me - - - . Same with "power tuners". They have the capability of storing more than one tune
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Officially, all cars 1996 and newer must be OBD2 compliant, but most jurisdictions using OBD2 for E-Testing only start at 1997 models because some 1996 models were not fully compliant. Only a very few
1995 vehicles had OBD2 capability as 1995 was "pre-standard"
In ontario the testers are directly connected to a central computer and it is virtually impossible to go from stem 1 to step 3 without completing step 2 first.
A number of years back, some crooks were running a "good" vehicle through the test 5 or 6 times, entering the Vin for one that would not pass. They made changes to the system that prevented that pretty quick.
Didn't have any significant positive effect on mileage and or power.
And the "test pipe" stopped being an option in 1996 with OBD2 testing pre and post cat O2 - unless you bought an O2 fake-out device that generated a fake O2 signal (actually, 2 signals ----)- which caused other problems (genrally a lot poorer fuel mileage and not much power improvement, if any)
Except "pending"codes don't turn on the CEL, and the CEL does not indicate if monitors have been "set"
That.
You have a good point. I need to recheck my facts.
According to the LA Times:
"Rather than meet the standards, the EPA says VW sneaked in the defeat device software to detect when the car is hooked up to a dynamometer, a machine that measures emissions. When emissions are being measured, the defeat device tells the car to operate at "dyno calibration," or full emission control levels, to meet the standards."
"At all other times, however, the software sets the engine to run on "road calibration," allowing the excessive emissions. How can the program tell the difference? By noting the position of the steering wheel, variations in speed and other data that suggest no one is driving the car, and thus it is likely being tested."
Well in California they definitely check via the OBD-II port. I had replaced a battery and there were no dashboard lights indicating anything. The first thing they did was to do a scan for codes.
The number of pending codes that is allowable varies by year of manufacture. A good shop will tell you the drive sequence to clear the pending codes for each model. A bad shop won't even know this information.
In California, one "smog check factory" in L.A. got caught because the state checked registered addresses of the vehicles and wondered why so many vehicles were being smogged at this one particular shop when their registered address was so far away. Few people will drive 25 miles in L.A. to get a smog check at a particular shop.
My brother-in-law regularly had inspectors come into his shop with test vehicles to be smogged. They would reveal who they were after the test. He did really well. He got one demerit for not telling the "customer" that they had the option of getting the vehicle repaired at his shop or any shop, even though he did ask if they wanted it to be repaired. But he still passed the inspection.
Actually it is not pending codes that are the issue. It is the readiness monitors.. Can't remember how many readiness monitors there are - but there's a catalyst monitor, a O2 sensor monitor, and EGR monitors, and O2sensor heater and cat heater monitor on some vehicles. These are the intermittent monitors that need to be "set" .
Setting the monitor just means they have been through one or more test sequences and have aquired valid data..
The rest of the monitors are contimuous monitors - misfire, component, and fuel system, nonitors.
The evap monitor, for instance, is only "valid" in a fixed temperature range, and with the tank between something like 1/4 and 3/4 full (not
100% sure of the actual numbrs). If you reset the codes or replace the battery on a vehicle with the tank full or almost empty you can NOT set the readiness monitor for the evap system - so virtually ALL OBD2 based emission test facilities will allow at least one monitor to be un-set or not ready.If you know what code is coming up, and want to "cheat" the system, if you can avoid setting that particular monitor, while setting all the others, you can sometimes get a vehicle to pass. You need to understand the drive cycle and what can cause the monitor you want dissabled to fail to set. (and it needs to be an intermittent or non-continuous monitor. The usual culprits are Cat, evap, or EGR.
It's usually documented as the FTP.
That answers what. But it doesn't answer HOW.
Finally!
Someone who both understood the question, and who posited an answer!
Of all the posters, you're the ONLY one who understood the question!
Sofa Slug wrote in mtn6qu$2in$ snipped-for-privacy@dont-email.me:
What I'm surprised at is that each state can have a *different* procedure.
In California, they use the dyno, but in many less technical states, they still use the dumb procedures.
This explains how they noticed there was testing going on.
The best answer to the question seems to be here, as noted by Sofa Slug:
Apparently VW lied at first, & apparently they can no longer sell the cars:
"The cheating came to light when the California Air Resources Board and the EPA pressed Volkswagen for an explanation for disparities found between lab tests and road tests of its vehicle emissions. The agencies didn't find the technical reasons offered by VW to be convincing and said they would not issue certificates allowing 2016 models to be sold until the automaker offered an adequate explanation. "Only then did VW admit it had designed and installed a defeat device in these vehicles," the EPA said. VW said it was cooperating with the investigation but otherwise had no comment."
It's interesting that VW didn't fess up until they were forced to.
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