i just bought an 02 s4 and checked the car for codes and got an EGR one, a SAI one and pre cat O2 but i was watching videos and searched other threads and they all say when start up the car sounds like a jet and mine doesnt make a sound at all like that so im wondering what happened or if it needs to be replaced and if its needed in the car??

 

what are the exact code numbers... P0xxx ??

 

here are the codes that came up when i hooked up the reader to it p1423 bank 1 AIR flow too low, p1411 bank 2 AIR restricted flow, and p1131 H02S 1 bank 1 heater resistence too high...if anyone can explain these would be appreciated thanks

 

Check the fuse for your SAI pump. If that is good you probably have the dreaded common garden variety "vacuum leak". Replace your vac hoses. Clean MAF. clear codes. drive for a bit. re-scan. report.

 

So I don't need any o2 sensors?...I have half the engine apart in my garage cuz I'm changing the coolant pump cuz I found a coolant leak and I'm just wondering cuz is a whole lot easier to get to with half the engine gone and I was also told to switch to the green coolant temperature sensor any thought?