# ESYS "Read (ECU)" vs. "Read SVT (Actual)"



## BlinkyShadow (Nov 1, 2014)

In ESYS's expert mode coding tab, in the "SVT actual" section, what's the difference between the two buttons labeled "Read SVT (Actual)" and "Read (ECU)". AFAICT they do the same thing (i.e.: populate the CAFD tree on the left from the car's ecus).

If I'm going to save my *.ncd for safekeeping, which of the two should I use? I think I've seen both mentioned in various FAQs.

many thanks!


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## shawnsheridan (Jan 10, 2009)

Normally they are the same. Read SVT returns the list of ECU's stored in VCM. Read ECU's actually queries the system buses, and returns the list of ECU's based on what it finds. Use either one.


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## gufemur (Jul 14, 2013)

How come almost every car I try, the read svt results in an error but it will read ecu no problem?


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## shawnsheridan (Jan 10, 2009)

Apart from F15, I am not aware of any other car that has this issue. Maybe your Connection parameters are not correct.


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## ap90500 (Oct 23, 2013)

I think that I had this same problem on 9/2014 F25, not sure though.


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