Audi Repair: Check engine light comes on, audi a4 quattro, audi a4

Question
I have A 99 Audi A4 Quattro and took in to the shop because the check engine light is on and wanted to know the codes. So heres what came up.
P1602 Power Supply terminal voltage too low.
P0116 Coolant Temp Signal not a plausible signal.
P0411 Secondary air injection system faulty flow.
Any ideas!!!

Answer
Sunds like your battery has low voltage, you need to replace coolant temps sensor and check secondary air pump.  Then re-set the codes and see if the system doesn't throw any more codes.  Pretty much typical things for a '99 car.  Let me know what I can do to help,  Jan