
How does the VW “defeat device” work - sosha
I&#x27;m curious how the software detected that an emission test was underway and switched on. Is there a switch or a standard way the tests are conducted?
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johnfc2014
When the EPA test cars, they use a piece of equipment known as a dynometer
which keeps the wheels moving on the driving wheels when the non-driving
wheels are stationary.

The ECM processor in modern cars detects a fault with traction control and
electronic stability in such cases. VW changed this into a "test mode" which
they could turn off the traction control, electronic stability and lower
engine emissions at the same time.

It is more likely that the EGR (Exhaust Gas Recycler) was enabled during the
"test mode" and disabled when in "road mode" as it reduces emissions by
recycling the burnt exhaust gases in the engine instead of using air from the
intake, since EGR is only found on diesel engines.

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JakDrako
Apparently, the software only checks if the steering wheel is being moved. If
the car is being tested on a platform and the steering never moves, "clean
mode" is engaged; if driving on a road, "Enough-emissions-to-choke-a-Humvee
mode" is enabled.

