Downstream o2 reading 0 volts

I'm having an issue with my downstream bank 2 sensor and figured this might be the best place to ask as I have the URD equal length headers and their o2 sim. About 3 months ago I got a P0157 code which is low voltage for Bank 2 Sensor 2, cleared it and it didn't come back until a week ago.

Ordered a new o2 sensor (Denso) and swapped it in, initially, I was getting .157 volts on the new sensor but it wasn't fluctuating at all, while B1S2 was fluctuating between .1 and .9 pretty quickly. Drove around for a while and P0157 came back which wasn't surprising.

I swapped Bank 1 and 2 sensors to see if the new sensor was dead but it functioned perfectly in the other bank and I had the exact same issues on B2S2. This led me to think that the URD 02 sim was potentially bad, I've had it for two years so I thought maybe some water got into it or something. Anyway, I unplugged all of the 02 sim harnesses and put everything back to normal, and got 0.0 volts on B2S2. Swapped the o2 sensors back around, still got 0 volts, plugged the o2 sim back in and I'm still getting 0 volts.

Currently, the only thing I can think is that I have a wire in the B2S2 harness that's torn inside of the sheath and is making an intermittent connection, although I'm not sure why this would have started recently as I haven't messed around with the harness since I installed the headers. Does anybody have other ideas before I splice in a new harness?

 

An open in the circuit sounds likely. May have started rubbing through when you did the installation and is just now starting to make metal on metal contact.

 

I figured a circuit issue was most likely, but oddly enough I just went down to the truck to take some trash out, started it up and bank 2 sensor 2 is reading .015 now I haven't messed with it or adjusted anything since it was reading 0.0 earlier

 

Small update in case this is helpful for anyone else in the future, B2S2 is stuck at .015v now from the moment the truck starts until it's shut off. This is with the URD o2 sim plugged in so I think that the voltage may be getting faked by that. Upstream looks good, no weird fuel trim or values there so it's definitely something with either the o2 harness for bank 2 sensor 2 or the URD o2 sim.

Gonna check it all with a multimeter this week.

 

I have the same set up URD headers and sim and I believe I had the upstream shut off with my tune. I’m going through the same problem with B1S2. I replaced B1S2. After a couple minutes it comes up from.055 to .2 B2S2 will be reading.3-.4 when I give it gas they pretty much equalize and read the same but when it drops Rpms they go to zero then back to .055ish and .3-.4. Not sure if I’m good to go or if I still have a problem. Thanks for posting I’ll follow along and see what happens.

 

Did you guys reach out to Gadget to see what he thinks? Curious to hear the results if you guys get it sorted.

 

I didn't reach out to Gadget directly as he isn't listing the o2 sim on the site anymore and I wasn't positive if he was up for discussing it. However I have narrowed the issue down to the o2 sim, with it removed both o2's are working correctly and the low voltage code is gone (although it's obviously been replaced by catalyst inefficiency codes now as I don't have cats). I checked the connectors/harness pretty thoroughly on the o2 sim and didn't find anything that would be an issue, and I popped the box open but the pcb is coated in epoxy.

 

It’s still an ongoing investigation. I haven’t pulled my simulator yet. I swapped the 02 sensors and tighten down my exhaust at the Y pipe and still have the same problem. I’ve been reading up on how to troubleshoot them. It’s supposed to rain this weekend so I’ll probably get underneath it again this weekend. I did throw a multi cylinder misfire last Saturday and it put the truck in limp mode. I pulled my plugs and they looked fine ( I had just put them in a couple weeks ago, I was popping the P0137 before I replaced them). I cleared the codes and a couple days later the p0137 came back. I’ve had my trans out a couple times in the last year so I’m not ruling out a bad wire quite yet. Started with the easy stuff first before I start dismantling it. I’ve also thrown a intake timing code twice in the last 6 months. I replaced the VVT screens and have had new VVT solenoids on order from the TW group buy for a couple months so I should be getting those soon. I pulled the timing chain inspection plate off and showed my tensioner to a couple people on here and they said it looks fine. Lol, and to answer your question no I haven’t contacted Gadget yet. Kinda working my way there slowly as I chase down the problem. I did reuse my exhaust donuts the second time I pulled the trans. I got about a 1/4 turn on one so I thought that might have be the trick. Still could be a problem if it leaking. Sorry for the rambling just trying to update what I have going on. When I figure out the culprit I’ll definitely post an update. You think you have these licked and a couple days later they act up again.

 

Like tires or brakes, I always like to replace things in pairs. Even 02 sensors. I just replaced all 4 02 sensors on my current vehicle.

 

Nothing to update but it’s been a month and figured I better check in. Started a little remodel in the house I thought was going to last a weekend and I’m still not done. CEL is still on nothing has changed. Gas prices are going to motivate me now to make sure the truck is running at 100%

 

Any way to run a temporary jumper around the harness? Could confirm or eliminate that its a broken wire.