I have a 2010 Journey. My battery had to be changed (btw is it normal for battery to last < 5years and esp since I've done much less driving due to Covid?). Got a new one installed but I didn't know that would cause a smog check to fail.
What do I need to do and how long to wait before I test again? Car has no other issues, I've read its 100 miles driving or some specific procedures to reset the codes?

I have a cheap bluetooth ODB scanner I never really used, can I use that to check the codes etc? If so please tell me specific methods/apps to use.

 

Here, when you fail a smog check, they give you the ODBII codes. If you have a scanner, you should be able to read the codes. If you can't figure out your bluetooth one, you can borrow one from AutoZone, and possibly from other parts shops. Knowing the particular codes being thrown will help you narrow down your causes. I'm 99% sure your new battery isn't the cause.

 

I can’t understand for the life of me how battery replacement would cause you to fail smog. I think this as a coincidence

 

I suspect not all of the emission monitors have run to completion. Depending on the state, you can pass with 1-2 monitors not ready / complete.

The OP needs to run the "Nissan drive cycle"

 

Once again, SonicVQ beat me to the punch.

Why would this be a coincidence? The battery being disconnected reset the ECU, therefore, SRT (System Readiness Test) monitor data was erased. If OP changed battery and 10min. later went for his I/M ("smog" you call it), then, yes, the car will likely fail. We do not know that interval, though, but it is feasible. All of the SRT monitoring/ testing data happens in the background. There would not be any "codes" or "CEL light" unless a fault was detected which prevented SRT from completing.

OP just has to complete the "Drive Cycle," as SonicVQ mentioned, and go from there. This thread has a detailed "how-to" on completing the drive cycle.

 

I stand corrected. My apologies. I've replaced dozens of batteries in my time and always assumed ECU relearning occurs when the car starts and sensors report their status back to the ECU, similar to when you replace TPMS sensors.

Nissan Drive Cycle. Learned something new today.

 

And 99.9% of the time this is exactly what happens. In this case, it seems OP changed battery and went straight to I/M testing without actually driving the car any considerable distance.

Just another of those headaches that this nonsense emissions hands us from time to time.

 

Exactly. Like my Evap hose that looked as if it aged 25 years while the rest of the hoses around it looked fine: https://www.myg37.com/forums/g37-sed...tem-error.html

Threw codes while my wife was driving the car as well, so she was anxious and wanting to pull off to the side of the road - service engine soon lights tend to do that to most folks.

As our cars are getting up there in years, its important to check as many of those PCV and EVAP hoses as you can reach while doing other service.

 

Drive monitors isn't Nissan specific. It's for every OBD2 vehicle out there. Certain conditions must be met before the drive monitor gets marked as completed. Some drive monitors require driving the car within a specific MPH window for "X" amount of minutes before it passes. The Evap monitor usually requires for the car to sit for several hours overnight.

 

It wasn't 10min, but it was a few hours later the same day. In between I drove maybe 5 miles. I did my DMV renewal a while ago and smog was pending so I didn't want to wait too long as I don't have new tags yet.
The guy at smog test shop said that a new battery will cause this. I also see this in many places online like - https://m.smogtips.com/smog-question...not-be-Smogged
I wish I'd known because this also cost me $40 for a failed test. Going to wait a few days and drive around now, also will try to use my scanner.

 

I was a smog tech for 3 years. If you change the battery it will reset the computer and emission monitors which are essentially tests that the computer performs in order to make sure the car’s emissions components are seeing the correct information. They will be “incomplete” until the computer sees the data needed to determine if the car is running how it’s supposed to. Drive it 50 miles on the highway then check the monitors. You have to drive anywhere from 20-100 miles. Trust me I’ve seen worse stories than yours