Lexmex

I am going to compare with a rescan of my own readings later today (before the Super Bowl).

aznlapin

Hey Lexmex, did you ever get around to doing the rescans? I know this is from 3 years ago...

I'm using an bluetooth OBD scanner with the Torque Pro app. I recently got a P0136 CEL (B1S2 02 sensor fault) and cleared it. Now waiting to see if it comes back. While I was on the app, I checked the other diagnostic PIDs. Looking at the A/F sensors, I got really weird voltage values.

The app lists the two A/F sensors as 02 Sensor 1 & 02 Sensor 5, don't know why it's like that. I get no readings for "02 volts B1S1" and "02 volts B2S1". Instead, for wide range voltage, I get 3.16 & 3.18 volts. Is this normal or am I looking at blown sensors. These are similar voltages to what trips1 listed in previous posts.

Also, is having 0.05V for B1S2 02 sensor ok?

Please help and thanks.

Lexmex

Do you have a screen capture of this at idle (after at least minutes with vehicle on) as I need to see exactly the screen you are seeing.

Reason I ask is that the sensors can will fluctuate and I never read anything right until the vehicle is warmed up.

aznlapin

Here are what I got after driving for 10minutes and then taking the reading at idle.
The AF sensors are consistently over 3volts and the B1S2 sensor is dead until driving for a bit. But that's normal since it has to warm up first, correct?

Attached also is the excel file with more data points over the range of 10min drive/idle.

Lexmex

Nothing here stands out to me nor in the excel.

Next time you get a CEL, a lot of programs have an option where you can see the point of error at what occurred/was going on at that time with the readings that triggered the code, i.e. freezeframe.

Generally (and I saw this from my own experience), is that you will get A/F sensor codes, clear them, they pop up again not too long later, maybe a week later, clear them, another week goes by, you clear them, then a few days pass, you clear the codes again. That is where you start to see deterioration of the A/F sensors. I do not really see them on this forum 'blow' per se.

aznlapin

Then does it mean having such a high voltage for the 2 AF sensors is ok? Thought it was supposed to be closer to 0.6v...

Didn't see a freeze frame function or something similar in Torque, but I'll look further into it and see if I find anything useful.

The B1S2 02 sensor has set off CEL P1036 for the third time now. Really hope its not the sensor itself, it's giving off the correct voltage. So I'm a bit confused.
Think I'll have to go do some digging around the sensor area and see if a wire or connect is compromised. Gotta wait for the snow to stop first.

Thanks Lexmex for the help so far.

Lexmex

Do check for the freezeframe, some of the more advanced programs do have a function/page/etc. for that, because it would be interesting to see the readings.

The ranges can fluctuate on the sensors, don't go by what this voltage says at this point or that point. When I've seen a dud or really deteriorated sensor, the numbers you will see show up on either freezeframe or in some cases the real-time scan will be WAY OFF from the numbers you have been getting above. As I mentioned before, my sensors (first my A/F sensors, then later the O2 sensor) went on the fritz over time, became more pronounced and then I finally switched them out, first the 2 A/F sensors, then I noticed the O2 sensor still having issues, and then replaced it.

What I am looking for on the freezeframe is what the voltage primarily and other readings were, and what speed were you going when the CEL triggered (if you know roughly the speed when it occurred (general range within 10 mph), that might help. There can be a trigger at 0.4 to 0.6 voltage, but not in idle, to cause a CEL, I want to know where that voltage was at a given speed and after it has fully warmed up, generally at 30 mph and above.

Moreover, this is an O2 sensor code (P0136), not the A/F sensor, and performance wise, this won't affect anything, just emissions (but that is important to your state where they do conduct testing). The O2 sensor is also cheaper than the A/F sensor.

My sensors really ate it from Mexico and it's gas down there (high sulfur) though the fuel did improve over the time I was there, I eventually got the codes coming back and back until I changed them and then nothing after that.

aznlapin

I managed to fish the freeze frame from Torque. This is from the latest time the CEL was triggered.
Sadly, I don't see any voltages on it. Sigh..

Peeked underneath the car. Didn't see any physical damage in the vicinity. So probably it's the O2 sensor that's shot. Guess it's time to visit RockAuto and get a Denso replacement.
Saw your DIY for the O2 sensor, it's great!

Lexmex

Such a low speed on this, something else is amiss here, but changing sensor should do the trick, amazon.com also has good prices on these sensors (that's where I got mine).

aznlapin

Thanks for all the help, Lexmex.

I'll come back and post the results once I get it replaced.