Error codes and O2 sensors

1998 Audi A4 2.8L Quattro
(i don't have a multimeter)

I've had error codes for years, but never bothered to fix them because I didn't need to but now I'm up for a smog check. I changed the O2 sensors and the check engine light went off, but a few days later the check engine light came back on and the error codes that I get are P1198 and P1199, which are issues with the post-cat O2 sensors, which are brand new. Now here's the kicker: I used generic O2 sensors, and the old ones I took off had a kind of heater core to warm them up, and the generic ones don't have it. Now I need to find a way to fix this so that I pass the smog check, I've looked up online the error codes and I've only seen the error codes pop up with other error codes on A4 and one incident where the 2 error codes popped up on their own in an A8. I checked the fuses for the fuel pump because I read in that A8 threat that they're related, the fuse was fine.

Now I don't know what to do, should I buy new non generic O2 sensors and change the ones I just put in? or is there something else that I should do?

 

You kind of answered your own question. P01198 and P01199 is post catalyst O2 sensor heater circuit malfunction. In most cases, it's one of the O2 sensors that the heater element has burned out on. The ECM monitors both heaters on a single circuit so if one fails, it'll have no choice but to set both codes. Then you check the resistance of the heater elements at the sensor connectors to determine which one is bad.

You'll have to put the correct sensors in. Those codes can also be caused by a broken wire in the vehicle harness, the ECM itself or the power circuit (think it goes through the fuel pump relay) but 95% of the time, a sensor is the cause.

 

I didn't want to buy new sensors (

 

So the O2 sensors you installed do not have a heating element and you are getting codes for non-functioning heater elements, sounds about right to me.

Heated O2 sensors are required components to pass smog, you will not pass without them. I would suggest getting the proper O2 sensors. You do not need to get OEM replacements, but do find the correct Bosch replacement and use those.

You will find the relevant part numbers here: OEM / Performance Parts for Audi, BMW, Mercedes Benz, Mini, Porsche & Volkswagen - ECS Tuning

 

Thanks for letting me know I needed to do that, I didn't want to but I did and I've cleared the error codes, but even though no error codes pop up when I plug in the one machine, it still tells me the MIL (check engine) light should be turned on. I guess I'll find out after I drive it for a week or so.