Replaced all of the vacuum lines and the MAF with another Bosch unit that I sourced from a 97 at a scrapyard. Retest had my Nox drop significantly lower than the legal limit but my hydrocarbon numbers were now above of the legal limit…next I treated the fuel with some sea foam and replaced spark ...

Update:

Replaced all vacuum line fittings. Cleaned MAF. Checked for exhaust leaks (non). Just got back from another failed emissions test with the NO ppm well into the gross polluter category. Any ideas? Appreciate any suggestions. Contemplating a visit to an independent Volvo mechanic as I am out ...

I will be emailing Aleksi for insight regarding the app. I mentioned the “bank 1 sensor 1 present” message as I thought it odd that there was no mention of the 2nd (downstream) o2 sensor. Both sensors were purchased from my local auto parts store so hoping that they are not counterfeits.

I will ...

Copy. Thanks again.
Not sure if it is relevant as I am not very savvy with the app (850 OBD2) as I have only previously used it to obtain accurate odometer reading and reset maintenance.
Yesterday I ran a scan utilizing the app and it is only showing “Bank 1 Sensor 1 present” in regard to o2 sensor ...

Both O2 sensors were replaced with Bosch (15097/15062). Strongly considering doing the same as that enabled the wagon to pass emissions 2 years ago. Any thoughts on the secondary air injection valve causing premature o2 sensor failure? Or is 2 years their typical life span?
In the meantime I will ...

Greetings,

Just returned home from failing emissions test due to well beyond max NO measurements indicating the engine is running too lean. Ran into this same issue 2 years prior when I became the owner.
At that time I replaced the catalytic converter (as existing was not CARB compliant), both O2 ...