Smdude35

Hello everyone. I cannot pass my state emissions because I have 3 sensors that won't ready.
- catalytic converter
- secondary air
- O2 sensor
I have tried a few different things for my sensors to ready without any luck. I have a 2001 Audi A4 1.8t Quattro awm. It has APR stage II tune with apr exhaust and test pipe. I am not pulling any codes or have any CEL. I tried replacing the secondary air and also tried a different ecu without any luck. The O2 sensors were replaced last year. Also tried to set readiness. Does anyone have any idea what the problem could be? Any advice would be greatly appreciated.

twentysevenlitres

Don't exactly understand the problem here:
No fault codes and no CEL, what's wrong?

Cat and Secondary Air aren't sensors. O2 could be the secondary sensor/s (post Cat) whidh would usually give a 'Cat efficiency' fault.

David.Norton

Well, if you have a test pipe I assume that you don't have a catalytic converter. In my state they check for the presence of the cat, and you will not pass if it is missing. I also suspect that the ECU will not set the ready codes if it doesn't see appropriate operation of the cat.

Smdude35

They don't check for the cat they just make sure everything is ready and passing. For my test pipe I have a spacer on the second O2 sensor so it should pass. I had the test pipe on last emissions test and didn't have any issues.

Smdude35

Hello, just an update on the fix. I did some more research and found out the APR stage II disables the rear O2 causing the OBDII results to NOT READY. I also found out my secondary air hose was cracked which was the reason why it would not pass with the other ECM I tried. I fixed the cracked hose and place the stock ECM and passed. I still have test pipe in. Thanks for everyone's input. I hope this may help someone else in the future.