On 9/18/2015 5:19 PM, Ewald Böhm wrote:
Apparently Volkswagen/Audi cheated on the USA emissions tests since
2009 to 2015 by turning off the EGR to lower nitrogen oxide emissions
ONLY when the car was being tested for emissions.
REFERENCES:
http://blog.ucsusa.org/volkswagen-ca...cle-recall-887
http://www.engineering.com/AdvancedM...EPA-Tests.aspx
http://hothardware.com/news/vw-inten...-482k-vehicles
etc.
My question is HOW did the car *know* it was being *tested* for emissions?
Can't speak for all states, but in California one of the first steps in
an emissions test is for the codes to be read via the OBD-II port. They
won't even proceed to the tailpipe test if there are incomplete
self-tests on the vehicle (I ran into this once when I brought a vehicle
in just after I changed the car battery).
It would be rather simple for the vehicle's computer to note that the
OBD-II port was active and to change the emissions system settings for
the next 30 minutes to an hour.
I suspect that most states with smog tests read the codes via the OBD-II
port prior to proceeding with tailpipe testing.
My brother-in-law had a Smog Pros franchise for many years and just sold
it last month. In some cases he would do pre-tests prior to hooking to
the state's computer so a vehicle could be repaired before being
labeled a gross polluter. A VW TDI would never pass a pre-test via the
EGA (exhaust gas analyzer unless the codes had been read first. But I
doubt he ever had done a pre-test on a VW TDI.
He told me that once he had a vehicle that was only slightly out of
compliance and he offered to repair it for $40. The owner declined,
saying he would fix it himself. Without an EGA that really isn't a good
idea, but the owner left then came back for his free retest under the
"Pass or Retest Free." So he did the retest and now the vehicle was so
far out of compliance that it was a gross polluter. The owner then
wanted to pay $40 for the repair and have it tested again but it was too
late. He could get the repairs done but the vehicle's status had been
sent to the state and now the owner had to take the car to a different
"Test-Only" smog check station and pay again. He also would have to now
get a smog check every year instead of every two years (that requirement
is no longer in effect).