Again the OBDII systems test many of the systems. They know if a catalytic
converter goes bad or even if there is a cylinder misfire. Even if the miss
fire is due a to a bad injector, vacuum leak, or an engine problem, the
system will know.
While hydrocarbons from leaky vapor recovery systems are a common failure
the NOx reduction is an extremely important part of smog control. This is
why the dyno tests were needed as an engine has to be loaded to produce the
NOx in order to test the reduction controls. Many cars use exhaust gas
recirculation as a control. Most VWs including the vanagon do have EGR  so
they must rely on the engine producing less and the 3-way catalyst taking
care of what is produced.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
James
Sent: Sunday, March 2, 2014 11:34 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Oil pressure warnings, WAS: Mann Oil Filter and lifters

Actually, they're trying to 'save us money' - the new test, that won't work
if the 'idiot light' is on,  only involves using the OBDII port - no tail
pipe sniffer at all!  It is thus  $20 cheaper than the old test (which those
of us who have vehicles like our '91 Vanagon still have to do, as there's no
OBDII to plug into).  I just had the 2003 Matrix in for it's test last week,
and was filled in by our local mechanic on all the ins and outs of the new
test.  Supposedly the leading cause for the check engine light to be on here
is a failure of the evaporative emissions control system, and it's those
stray hydrocarbons that they're most worried about - makes sense, carbon
monoxide isn't nearly as serious a pollutant as the various aromatic
hydrocarbons in gasoline are.

James
Ottawa, ON