Different Idle speeds – FWD & 4Motion?

In my continuing quest to reduce the idle speed in my b5.5 V6, I came across a reference in the Bentley that “All-wheel drive idle speed should be 620 to 740 rpm” while the “Front-wheel drive idle speed should be 710 to 860 rpm.” It then goes on to say that “If engines of front-wheel drive vehicles run at 620-740 RPM, check the control module coding.”

This implies (I think) that there is some code that could be put into the control module that would result in a lower idle speed – which is what I want.

Does anyone know why 4Motions would idle slower than the FWD? It seems ridiculous to me, but……….. Also, any info on what to change with the control module coding?

TIA!
Richard

I've not tried it, but in the first section on idle speed adaption it should be possible to change.

http://www.ross-tech.com/vag-com/cars/passatb5.html