O2 Sensor little to no voltage Bank 1 Sensor 1

[jmonica]

Hi. I'd like to preface this by saying that I realize that there are a lot of diagnostics that should be done to diagnose and pinpoint the problem, and I know that throwing parts at it is not the right way to go about fixing this.
Unfortunately I don't have the time. I already have a new o2 sensor (upstream) that I can't return and I don't mind throwing parts at it in an attempt to fix it quickly given my current situation.

I realize this isn't the smart way to go about it, call me stupid, I don't care, I just don't need a lecture on how I'm not following proper procedures and how I might be wasting money by throwing parts at it before I've done a thorough diagnostics routine on it etc. I totally get it. Nornally I would do just that.
I don't have the time right now and I'm in a bind. I am very limited to how long I have to work on it in its current location and in my current situation, and so I'm asking for help.

As I mentioned, I already have a new o2 sensor for it on my shelf.
Problem. P0131 and 0171

My half-a$$ed plan is to check for a wiring problem to the sensor given the lack of voltage to it.

I just need to know if the sensor may be bad or if the wiring is bad before I attempt to remove it because I know that replacing it is going to be a nightmare and I'm going to ruin the existing sensor while attempting to remove it.

I just hope I can get the old one out in the limited time I have.

I'm not sure what I should expect when I check the wiring to it. Should I have a constant 12v to it?

I've already checked for vacuum leaks, checked for exhaust leaks before the sensors, and didn't find any.

With the attached snapshot of the live sensor data, the top graph is the downstream sensor data. It changes when I rev the engine.

The bottom graph is the upstream and the voltage to it is between 0.0 up to 0.07 so basically no change when increasing RPMs.

The engine was warned up to normal operating temp before running scanner tests.

I guess what I'm asking is if you were in a bind, and if this was your situation, what would you do to check out the problem starting with the easiest, fastest things to check to determine if it is the O2 sensor that's bad? Not because I'm too lazy to research it, learn about it and spend the time to do it right, but because I don't have that luxury this time.

I sincerely appreciate any guidance and your understanding. Thank You

 

[Mooseman]

Personally, I would just throw a new sensor at it and since you already have one, just change it out. The wiring and connector are right next to the PS pump so easy enough to do a quick visual check.

Change the sensor and clear the codes. Check for the B1S1 sensor to alternate up and down pretty regularly. B1S2 should be pretty steady indicating the cat is working, which is all that sensor does.

 

[jmonica]

Personally, I would just throw a new sensor at it and since you already have one, just change it out. The wiring and connector are right next to the PS pump so easy enough to do a quick visual check.

Change the sensor and clear the codes. Check for the B1S1 sensor to alternate up and down pretty regularly. B1S2 should be pretty steady indicating the cat is working, which is all that sensor does.

Ok Thank You Moose. I did the a few minutes to check the wiring and I at least know there's voltage to it. I'm going to pickup some map gas and a better o2 socket and have it. Fingers crossed it is just the sensor. I really appreciate your help. Very much.

If and when I do finally get to pass inspection, next is to start replacing all of the worn out parts in the front end, and then finally, hopefully I can get at least a weekend or two this summer, riding in the car instead if lying under it!

Thanks again. I will post results. Have a great weekend!

 

[jmonica]

It just never stops. I replaced the upstream O2 sensor last weekend. Feeling like a new man, for a few days, no CEL, but the car still felt sluggish to me and guel mileage didn't go back up. It did a tiny tiny bnit but it's still way off what it should be.

I recently found and thought I'd fixed problems with the evap system as well.

Anyway with no evap codes for a few weeks and my new o2 sensor, I thought I was close to having roblems fixed, but no.

And as normal, the CEL light is back on and now I have p0135 and p0446. Yesterday when I started the car after it sat overnight, it was stumbling and missing for a few seconds until I revved it up a little. It's never done that.

I checked voltage to the O2 sensor (Upstream) and it's at about 9.4v. Not 12v like it should be, so now I need to try to find a bad wire or ground. I thought I had the ground problem licked as I spent a day just cleaning all of the engine and body grounds I could find, but pehraps I am missed one and it's causing low voltage to the O2?

I'm going to test the O2 sensor heating circuit and check the voltage to the sensor again and go from there.

Then address the 446 code.

I'm so burnt out on just trying to get this POS running normally long enough to get it to pass inspection and each time I fix somthing, a few days later another set of problems.

I was getting a bunch of black carbon from the tailpipe upon cold startup. That seems to have subsided to some extent but not completely.

I have no doubt the catalytic convertor is probably ruined from it running rich. And it was running lean before i relaced the US O2.
SO I'll get to testing that at some point.

Just trying to figure out what the best place to start is on this new set of problems.

 

[Mooseman]

First of all, what brand O2 sensor did you use?

Did you ever get this code with your old sensor? If not, I'd highly suspect the new sensor. Just because it's new doesn't mean it's good (seems to be a common theme since 2020)

Easy enough to check if your ground is good. Check between the black wires at the connector and battery negative terminal. And using the schematics, check for proper continuity between the O2 sensor to the PCM connector.

A code P0446 could mean one or more of the following has happened:
Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM (very unlikely)

 

[jmonica]

First of all, what brand O2 sensor did you use?

Did you ever get this code with your old sensor? If not, I'd highly suspect the new sensor. Just because it's new doesn't mean it's good (seems to be a comamon theme since 2020)

Easy enough to check if your ground is good. Check between the black wires at the connector and battery negative terminal. And using the schematics, check for proper continuity between the O2 sensor to the PCM connector.

A code P0446 could mean one or more of the following has happened:
Faulty vent valve
Open, short or excessive resistance on Vent valve control circuit
Blockage of vent valve
Bad PCM (very unlikely)

Hi Mooseman. Thanks for the speedy reply. To answer the question, I was not getting this code (0135) before the new cheapo sensor. I was getting something like 1155 related to the heating element circuit on B1S1. I know ACDelco is the way to go, but I had the new sensor on the shelf and not a lot of time, so decided to swap it. Also had a flatline or no activity on US O2 sensor the live data.

After some testing a few minutes ago, I have activity on both O2 sensors.

I have between 3-4 ohms of resistance on the heater wires at the sensor.
I have 12.5v on the wire going to the sensor
I have no resistance on the ground wire to the negative battery terminal.

What is strange to me is if i check the voltage between the positive wire and the ground wire at the connection going to the sensor (when it's not connected to the sensor), I only get about 9.x volts. I realize the ground comes from the ECM. This was all checked with a cold engine.

Also the resistance on the heater wires from the sensor went up to 6 volts when the engine was completely warmed up. It went up from 3.x to 5.9 ohms. I don't know if that's supposed to happen or not.

So I'm not sure where to go from here. I saved some live data on the O2 sensors and the short and long term fuel trims.

Honestly I don't know what else to look for in the scan data to help isolate the problem.

I don't think the 0446 code is related so I am saving that for another thread, after I fix the 0135.

I also discovered what it is that makes the vehicle sound like a Jet engine on take-off for the first 20 seconds after startup. It's not the cooling fan, as some had suggested, but again a topic for another time.

One question I have. On the air filter box there's a smaller hose (about 1-2" in diameter, that connects to the side of the air filter box. The plastic connector broke on mine so its just an open hose now. Besides the risk of foreign matter entering it, could that cause a major problem before I receive the replacement air box? I had a K&N CAI on it and put the stock setup back on. The hose I am referring to connected to the underside of the K&N air intake hose, that went to the throttle body. It connected after the filter, but before the MAF sensor. I don't know what the ramifications of not having that hooked up to the air filter box are if any? On the stock setup, that hose just goes into the air filter box, I assume to filter the air.

Thank You! I'm so grateful for all of your help Moose! I really am.