2014 Chevy Truck Suburban 4WD V8-5.3L

Can we assume you swapped with B2S1? Who's to say that sensor is not functioning as designed? I know only coded for B1S1, but new OE sensors are cheap. Way cheaper than throwing new injectors in it. How did you test for exhaust leaks? Use a smoke machine if available.

If you can monitor b1s1 vs b1s2 on a graph I'd compare sensitivity. May have a bad terminal in the O2 plug on b1s1. Someone could have jammed something in it to test it and damaged the terminal. It doesnt take much. Take the pins out and recrimp/shape them so the have good tension on the Male pins on the O2 sensor plug. You may have a bad PCM too. That'd be last resort.

Have you checked ground at the engine using volt drop? I've seen several posts in IATN and replacing both front sensors with OE and it fixed the issue.

Hi Ray, you said you checked fuel trims, I would recommend checking them at different speeds of engine like at idle, and 1500 rpm and 2500 rpm ( make sure oil is good) and see what fuel trims r doing, and in your write up, I don't know if it was a typo but I'm almost sure those part numbers are different for 02 sensors on same bank, so not for sure that there is a difference between upstream and…

Yes that was a typo sorry about that I edited it thanks for pointing it out dont want to confuse you guys

… I must have seen it in it's pre-edited form… Dan H.

… Are you sure the application (part # ) is the SAME for a B1S1 and a B1S2… I find that they often are NOT the same… even left to right Pre and post cat sensors being different #'s . … Dan H.

Hi Ray, I would start testing for this code by reading the code set criteria in your SI. I have it below so you don't need to look for it. P015B or P015D The ECM detects that the HO2S 1 sensor has an initial delayed lean-to-rich response when the voltage has not increased above 350 mV within a calibrated value of accumulated air flow. Then I would pull up the freeze frame data for that code…

FRTD (Flat Rate Test Drive) interesting! are there particular videos teaching the fundamentals of this? Always striving to get better will post freeze frame data tomorrow!

Ray, I don't know of any videos but it is a pretty simple process, once you set up a vehicle /scan tool a few times it becomes second nature. Here area couple things from Albin Moore to help. Fuel System Lean Bank 1. Fuel Trim for Driveability.

Will definitely give a read later in the evening thanks !

Install 2 new OE gm front o2sensor. Only gm, never aftermarket. Only the OE sensors have fast enough response times to satisfy that code.

I agree with Eric much more can be tested & when does this code set or just always runs in tune …Usually Rich to lean is the slow switch , any chance of back pressure involved here .

Yes I never heard of FRTD until yesterday did some research yesterday definitely will have to learn that technique! just ordered an exhaust back pressure gauge last night thought about it since I only ever seen 1 clogged cat in my 8 years in the business and that was when I was an apprentice well I'll always feel like an apprentice in this business lol

1 plugged cat in 8 years?? Incredible. We usually see 10-15 a year.

Do you happen to use a backpressure gauge to verify or what method do use to verify other than honeycomb broken inside rattling noise?

… Yup … a dedicated BP gauge …worth it's weight in Platinum , Rhodium and Palladium … Dan H.

Any specific bp gauge you recommend to get that measures the best? Or just any generic one from amazon will do?

… Mine is an Ashcroft Kit …0 to 8 PSI… stainless braided 3 ft hose … keep it in a pistol case… works good … had it a long time … forget the cost… to long ago … Dan H.

… As a side note Rhodium is now (market price) $30,000 per OUNCE (USD)… no wonder the thieves/crack heads can't resist… Dan H.

just had a big heist of cats this past summer south of the Wisconsin border in northern Illinois it was 2 different groups of opioid addicts lol

Scan data will reveal a plugged exhaust, in cylinder transducer also is good. Seat of the pants feel, followed up by whatever backpressure test I feel is warranted. Usually screw a tester in a 02 hole. Especially with multiple cats to verify the offending one.

just curious What pids are you looking at for scan data? short fuel trims by any chance?