Anyone done any exhaust work? I’ve had left and right o2 sensors for after the converter codes for the longest. Considering the wiring was a bit mangled from a previous owners repair, went to shop after suggested replace both sensors as a possible short.

Finally replaced sensors and redid wiring, couldn’t find a harness for those though, so had to heat shrink. Everything went smooth but codes still come back (I use my plug in ob2 reader that Bluetooths to my phone). I did a quick YouTube search and one video seemed to imply if the (original position) o2 sensor is too far back from the cat, it may not be warming up enough…but I thought the wires controlled the heated part? Plus my entire exhaust is still factory, except the rear o2 sensors.

So idk.. not sure if I need to just continue driving so the system can reset itself, or if my cats are just not getting enough flow. More importantly, does it even matter? This was a $250 repair when adding parts, and I almost feel it didn’t do anything…hence why I put it off for so long. The upper 2 sensors don’t seem to be generating any codes.

Which codes are you getting? N/I ECM's are pretty good at discriminating bad sensors from bad cats, and there are distinct differences in the codes you'll get depending on what's wrong. Post the exact codes you're seeing and maybe we can be more helpful.

P0141 and P0161



That's kind of why I had wanted to go to a dedicated muffler or exhaust shop to get this done. But I had a hard time finding a place available. Not to mention, the hypothesis seemed like the previous aftermarket wiring had gotten wet, and possibly even nicked the wiring on road debris. Thus shorting out the sensors. Not to mention, whoever did it last cut the OEM sensor harness and gave it universals. Bad Bad idea especially since now they are so readily available for almost the same price as the universals (only Bosch has universals for this that I've seen).

I can clear the code as much as I want, and it’ll stay off while driving. But soon as I turn engine off and turn it back on, check light comes back on.

Those codes are for the heaters, not the sensors themselves. The only thing the two sensors have in common is their 12V supply, 7.5A fuse #3. See if it's blown, and check for 12V on the Green/Red wires at the sensors.

Okay cool, I’ll check the fuses down as well to see…

Update: yes RRo2 sensor fuse was blown. I shoulda tried that first before replacement lol. But the fuse probably blew due to an issue with those. They were fairly burnt at the tips.

I only suggested cats because I’ve had a long going oil burning issue. But definitely in no hurry to replace…ever lol.

We are VERY lucky to have Vstar here

Yes of course! But I think I might of spoke too soon. 1 code did go off, but bank 2 sensor 2 is still pulling up a code. My handy phone code reader is showing no voltage.

Just great. And I can’t find any other sensor fuse that controls that except the front fuse. I just see RRO2 sensor and FRo2 sensor. Is that rear right and front right, or the same for both front and rear.

Check the wiring for the one that's dead, and if you don't find obvious problems, compare heater element resistance between the good and bad rear sensors. Fuses occasionally pop from old age and no good reason, but it doesn't happen often. Chances are the dead sensor or its wiring popped the fuse.

Well that’s the thing: both downstream sensors were replaced last week. I took it to a shop the other day to have it done because it was too hard to break them loose from ground level.

At this point I’m over it lol. To get it checked again I’d need to schedule another appointment. Idk. It’s definitely running better though. Accidentally hit 100 mph trying to pass a couple of idiots on the interstate the other day so…certainly no power loss lol.

Update:

Did another code scan and the rear 02 is definitely being impossible. Idk what's going on with it, but now wondering if I wasted money buying new ones. The bank 2 sensor is still off. Took a screenshot of the weird random codes it's been throwing out:

If those codes are all current, the bank1 heater is open-circuit (P0141) and the bank2 sensor is malfunctioning, probably flatline since you're getting P0158 and P0159 together. Flatlines are usually from an internally-broken sensor, but since you also have a problem on the other bank, it could be physical damage under the car or wiring damage depending how your harness is constructed.

VStar650CL wrote: ↑

Tue Oct 19, 2021 5:21 am

If those codes are all current, the bank1 heater is open-circuit (P0141) and the bank2 sensor is malfunctioning, probably flatline since you're getting P0158 and P0159 together. Flatlines are usually from an internally-broken sensor, but since you also have a problem on the other bank, it could be physical damage under the car or wiring damage depending how your harness is constructed.

It seemed initially that I was only getting 1 code: heater circuit. Changing the fuse fixed the 1 side but not the other. These other codes didn't appear all at once until "later". That is, after driving around and turning car on and off. So those are mainly a build up of codes over the course of a couple days.

This is why check engine lights I'm learning: are just a nuisance and need to be programmed to go off by themselves lol. I have codes for my EGR and Evap that have randomly come and go, despite cleaning and replacing some of the components.