1999 Audi A8 ABS and Airbag lights on dash

Hello - Sorry to say since it is a safety item your code scanner may not pick up the codes. You have to have a SRS code scanner. This is even needed to reset the light even if there is no problem It should cost about $40 or so to check/reset. Although your vehicle got wet, I recently worked on a Mercedes E320 and had to pull the airbag to replace the multifunction switch. Once replaced I turned the key on to check it out. It worked fine but turned on the airbag light. The airbag controller runs its checks. Once it does a check to see if all the airbags are working, if it finds one that isn't it throws the codes. So you may have to take it to the dealer, let them hook it up.....do the test of the system and clears the light. Also, it looks like you may have a recall on your vehicle. The dealer may fix this for free. Please contact the dealer service department, give them the VIN number of your car and have them check on this to see if it applies to you.