Help. My e39 is very slow

[rrah1movv]

Hey everyone,
About two months ago, I bought a 2001 BMW E39 530i. Previously, my dad had the exact same model, and even though we barely maintained that one, it was noticeably faster than mine is now.
Currently, my car is running Euro 0 software. One issue I know of is that the DISA valve is faulty, and I’m planning to replace it soon.
Another problem is that the ASC/DSC warning light is constantly on. Several mechanics told me that my ABS module is faulty, but I believe the ABS unit itself is in good condition.
Any suggestions on what else could be causing the loss of power and the ASC/DSC light? I’d really appreciate your help or advice from anyone who’s dealt with something similar.

[konner412]

Hello fellow e39 friend! A faulty disa flap will cause decreased power. Fix that first before trying anything else. With age you could also have a catalytic converter clogging up so keep that in mind which can cause the same issue. That is what I am currently dealing with on my 540i. I would recommending getting a good scanner that will read “ghost” codes that a typical pocket scanner won’t pick up. It will be helpful diagnosing the car accurately.
Referring to the ABS/DSC warning triangle. The DSC hydro unit has an electrical module which can fail internally. I had this same issue. Very simple to remove the electrical component and send to a reputable shop to rebuild the motherboard. There are a few places on eBay that will do it. There is also a possibly of another issue causing the ABS light. For instance, a faulty wheel speed sensor/wheel bearing or even the steering angle sensor. As I mentioned before a good scanner can pick these codes up, or if you can get access to ISTA.