'98 A8 4.2 TPS - and Idle issues
 

My car started having some shifting, and surging issues recently, and when I told my Audi mechanic (who is also my brother) he said they didnt do transmissions. So I have some one else look at it. 80 bucks and three hours later he tells me that its the TPS...well as soon as we start it up it throws a p1509 Code - Idle system electrical malfunction. Today when I started the car it died instantly. I had to hold the gas down to get it to run.

So my question is...is the bad throttle position sensor causing this code?
or did this guys break something?