VAG-COM for Ur's?
06-19-2003, 10:05 AM
#5
AudiWorld Super User
You are on the right track, but be more specific.
The frequency valve DC is how the F/TCU controls mixture. By reading it you are monitoring this control circuit. But there is one related "diagnostic" or tuning aid...
06-19-2003, 10:11 AM
#6
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AFAIK, the DC is a diagnostic reading
the DC fluctuates with the readings from the various sensors (O2, air temp, etc.) during warm idle, so it can be used to determine all types of other problems with the car.
I don't think your talking bout the CO adjustment screw.?
I don't think your talking bout the CO adjustment screw.?
06-19-2003, 04:30 PM
#7
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Re: Aaa ha ha ha ha. No. There is only ONE diagnostic function on the car.
Specifically, if there is a defective idle switch or intake air temp sender (or the wires are crossed/crudded), the engine speed is limited to 4000rpm.
That's the only diagnostic function that I'm aware of.
Scott J
That's the only diagnostic function that I'm aware of.
Scott J
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07-21-2003, 08:51 AM
#8
AudiWorld Super User
Not really, it is simply the ECU's way of controlling the mixture. Answer enclosed.
The one diagnostic feature is the ECU going to a 50% duty cycle on the frequency valve when both WOT and idle switches are closed.
Using this is a good way to set idle CO values with a gas analyzer when the engine is hot and normally running closed loop.
Using this is a good way to set idle CO values with a gas analyzer when the engine is hot and normally running closed loop.
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