Hey all, New to the forums here and am in need of some help. I am having problems with my 2000 A4 1.8t. Lately, if I have the car running and turn on the A/C the engine almost completely cuts out. I lose most all power. Is there anything obvious here to anyone, alternator, anything electrical? Nothing seems to show when the engine is scanned. Thanks for any help in advance.

 

Anyone? Not even a hey whats up? lol

 

I coulb be couple of things,
A sizzin A.C. clutch that draws too much power from the engine, that would the first thing
to check, other wise you would need wiing diagrams to see wat protective devices are in the
circuit to compasate whn the compressor comes on ...

 

Well, had the codes pulled today, its reading a P1128 code(Upstream Heated 02 sensor swapped)? Something about the o2 sensor. Can anyone elaborate on what this code means since autozone cant read "dealer codes" so they say? Im sure it means that I need a new one but which one is it? Any help is greatly appreciated.

 

i wish i can help.. i really dont know anything about a/c or what your saying.. but what i reccomend is maybe your battery is dead and when you turn your A/C on it will take too much juice out of the alternator which might cause the engine to idle slower???

somthing like that may just be a possibility...

 

I'll look up later. Could be bad oxygen sensor, precat

 

Bentley says ...
Bank 1, mixture adaptation (mult.)
System too lean

Check fuel system pressure.
Check Mass Air Flow sensor.
Check intake system for leaks (false air).
Check oxygen sensor before cat.
Check oxygen sensor post cat.
Check fuel injectors.

for what it's worth ... i'd definitely start with precat o2 sensor. they seem to cause alot of problems.

 

VAG17536
P1128
Long Term Fuel Trim mult.,Bank1 System too Lean

O2 sensor is likely the culprit, or the MAF.
Being lean is not a good condition to have.

 

check the two main vacuum lines, the one that goes from the mani to the fpr and the one that goes to the dv. i got that same code a few months ago, i was ready to change the o2 sensors, ended up that both of those vacuum lines were dry rotted and leaking bad, i replaced them and she's been fine ever since.

 

Thanks alot all, I have been out of town and will definately take a look at all the stuff you all offered. Ill keep you posted on the out come.