my wife's 2000 A4 went into limp mode while I was at work..I'm a merchant seeaman.The only info from her was that it doesn't work! I bought a OBDT2 reader from Checker but it didn't work. A friend put it on his computer and I got 6 codes. We erased them all and the one that came back was-p1602 power supply terminal 30 volts to low.The ones that didn't return were 17965,p0140,p1648,p81626 and p1624. This car had the computer done on an Audi Forum group buy abt a year ago, I forgot the name of the company. Any help--advice would be appreciated. Thanks----I'm on the Big Island, Hawaii and don't know anyone who works on Audi.Also the pop-off valve goes off @ 40mph!!!!Thanks again.....ALOHA!

 

http://wiki.ross-tech.com. Also, how did your friend scan it?

Of note:

17965/P1557/005463 - Charge Pressure Control: Positive Deviation
Possible Symptoms
Reduced power output
Limp mode
Possible Causes
Boost Pressure too High
Hoses/Pipes incorrect connected, disconnected, blocked or leaking
Charger Pressure Control defective
VNT (variable nozzle turbo): nozzles stuck
Solenoid Valve for Boost Pressure Control (N75) defective
Possible Solutions
Check Hoses/Pipes to/between Components
Check Solenoid Valve for Boost Pressure Control (N75)
Check / Clean / Replace Charge Pressure Control
Check / Clean mechanism for variable nozzles

 

Thanks for the fast reply. My friend has a shop and a computer for diagnostics but he doesn't work on Audi, mostly BMW, Porche and Mercedes.He just hooked it up and read the codes for me. I guess I need to look at hoses and the pop-off valve?

 

You should scan it with Vag-Com. www.ross-tech.com

 

Does the diverter valve make a lot of noise when it opens? This sounds like a turbo pop-off valve. Started doing it at 50mph now at abt 40mph,lift off the gas and it goes away.

 

I don't hear mine.