The revo chiP was installed, and now my engine check light is on??? whats wrong? The guy took it off with the computer but now its back on, and he sed something about bad battery??? could it be that my new bypass valve isn't in yet?

Thanks

 

Well there is no way to be completely sure of what the problem is unless you buy/borrow a Vag-Com. It has to be the single best investment for an Audi driver.

www.rosstech.com

 

Doubt it's the DV. Like Jestnomen said, get a VAG and read the codes directly.