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Old October 5th 15, 08:05 AM posted to alt.home.repair,rec.autos.tech,sci.electronics.repair
mike[_22_] mike[_22_] is offline
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Default EPA caught VW cheating - how does the car know it's being tested?

On 10/4/2015 9:04 PM, Clifford Heath wrote:
On 05/10/15 13:33, sms wrote:
On 10/4/2015 2:39 PM, Klaatu wrote:
According to NBC, the emission controls were altered when only the front
wheels were turning, as on a dynometer.

I don't know about diesels, but newer gasoline powered cars in
California don't use the dyno anymore. The levels are all read from the
sensors via the OBD-II port, at least in California.


It's trivial to detect that the car is not being driven.
No steering wheel motion, no compass variation, no accelerometer (if
fitted), no... you name it, I'm sure there's a long list of candidates.

YOu're overthinking it. It's about driveability
If the rear wheels ain't turning, you should turn on the emission
controls. When the car is stopped in traffic, might as well make it
clean. Performance isn't an issue when stopped.
I'd have taken it a step further and made it clean whenever driveability
isn't compromised...like when not accelerating at a rate faster than
you could do with the emission controls functioning.
Probably would never have been detected.