o2 sensor monitor readiness woes -smog check

[alpin3m3]

Good Morning All,

I can't seem to get my o2 sensor monitor set for smog. I have put about 500 miles on my car in the past week trying to get all my monitors ready and they are all good except for the stubborn o2 sensors. I have put multiple FTP drive cycles on the car with emphasis on the 15 minutes of driving at less than 60mph and below 3k rpm. I can't seem to figure out why it's not ready. I'm using an OBD2 dongle and car scanner app to check the monitors.

The car used to have a alpine tune under the previous owner but he removed it for smog 2 years ago and flashed back to stock. I had test pipes on the car with o2 sensor extenders but I removed the test pipes and used clamps to attach the stock cats back on. I never had the car tuned even when running test pipes as the o2 sensor spacers got rid of the check engine light.

My car isn't completely stock as it has a CA legal dinan intake/elbow and underdrive pulley, but these are both minor modifications. Throttle accuators were replaced a few years ago. post cat o2 sensors were replaced a year ago but not the precat sensors. The only other things I can think of are:

-Car despite not being tuned, was coded by alpinemss to get rid of my airbag light from running aftermarket bucket seats. I had some other stuff coded in as well but this shouldn't effect monitor readiness correct?

-Battery may be weak, I throw the car on my trickle charger so maybe it's masking the symptoms of a battery on its way out

-Maybe I'm running an older version of the OEM DME software?

What else should I do/ check for so I can get this stubborn monitor set? Am almost at my wits end

Thanks in advance Fellas, hope you're all having a great weekend!

[NiBe]

Hello, O2 sensor monitor gets set quite quickly I would say under 10 minutes of driving. So there is probably some problem like a bad O2 sensor or caused by the tune or exhaust. Old version of DME or weak battery do not seem to me as probable culprits. Did you read DME error codes?

[akkando]

O2 sensors are quite sensitive to twisting or pinching of wires when installed.

[PandaM3]

Are the original cats placed back in? Or still running 02 spacers and test pipes? I bet you just have bad O2 sensors.

I didn’t know Dinan made a carb legal CAI… I need to look into that rather than swap my intake every time I go for smog.

[alpin3m3]

Originally Posted by NiBe

Hello, O2 sensor monitor gets set quite quickly I would say under 10 minutes of driving. So there is probably some problem like a bad O2 sensor or caused by the tune or exhaust. Old version of DME or weak battery do not seem to me as probable culprits. Did you read DME error codes?

Thanks for the reply, I had one code CDB7- this is edc module related as my edc has been unplugged and coded out in favor of KW coilovers.

Originally Posted by PandaM3

Are the original cats placed back in? Or still running 02 spacers and test pipes? I bet you just have bad O2 sensors.

I didn’t know Dinan made a carb legal CAI… I need to look into that rather than swap my intake every time I go for smog.

Yes I clamped the stock cats back on with cheap amazon band clamps and removed the spacers. The monitors were actually all ready with the test pipe/o2 spacer set up but I was scared it would fail the visual. The CARB legal Dinan intake is a bit of a misnomer. The Carbon fiber elbow is CARB legal and comes with a decal/EO number, but the dinan filter is not CARB approved. But the filter can not be seen as it's underneath the stock airbox lid .


Thanks to everyone who replied, my monitors are all set and I'll take it in for smog first thing on monday. I noticed the cheap band clamps I was using to mate the oem cats to my hacked up x pipe were leaking a little. I thought the leak wouldn't matter since it was after all the o2 sensors. On a whim I decided to remove the clamps and wrap a cut piece of a soda can around the exhaust before clamping them down again. Surprisingly it actually worked in fixing the exhaust leak and sometime after that the o2 sensor monitor finally showed as ready.

I have a theory that the leak was sucking in air and despite it being after the o2 sensors, the post cat o2 sensors are sensitive enough to pick this up and refused to set. I could be wrong about this.

[bstone801]

I had this same problem for a long time running test pipes. I replaced all 4 sensors, had my test pipes welded into place instead of clamped and I have yet to have a problem yet. Clamps are prone to shifting and getting exhaust leaks near the connections of your cats/test pipes. Just my experience.