2013 Escalade ESV P0131 and P0171

[skpyle]

Hello Gentlemen,

Well, the honeymoon is over with my 2013 Escalade ESV Premium. Last night, the check engine light came on. This morning, coming out of work, the remote start didn't work.

Once home, I dug out my neanderthal scanners and pulled codes. I have the following DTC's stored:
P0131 (scanner called it 'O2 sensor circuit low voltage bank 1 sensor 1') Alldata calls it 'HO2S Circuit Low Voltage Bank 1 Sensor 1'

P0171 (scanner called it ' System too lean bank 1') Alldata calls it 'Fuel Trim System Lean Bank 1'


NOTE: I did not 'feel' the check engine light come on. I just happened to look down and see it on. The vehicle drove fine (no different than my limited 5 days of driving) last night and this morning.
Also, this Escalade is a Flex-Fuel model.

I have done some quickie google-fu and general consensus is:
P0131 is likely a failing bank 1 primary O2 sensor
P0171 is likely an air leak.

However...according to Alldata, conditions for setting P0171 include P0131 NOT being set. Meaning two different issues? I had been caught in the 'chicken or egg' mentality. Meaning, was I seeing codes for a failing O2 sensor, or is the O2 sensor reacting properly to an air leak?

I used both scanners to pull some live data at idle. NOTE: I have a clone Tech 2 on order, but it likely won't be here for another week.

FRP(psi) 43.1-43.9
ST FTRM1(%) -0.8 to -2.3
LT FTRM1 (%) 2.3
ST FTRM2 (%) -1.6 to 0.0
LT FTRM2 (%) 2.3
O2S11 (V) 0.100 to 0.750
O2S12 (V) 0.645 to 0.670


Looking at Alldata:
P0131 is set when the HO2S voltage drops below 0.050V. Looking at what I believe are my primary O2 sensors, neither is below 0.100V. However, note how sensor 1 varies while sensor 2 is relatively steady.

P0171 is set when the long fuel trim for bank 1 is greater or less than a calibrated value. I sorta got lost looking at that one. I did note that both long fuel trims were stable at 2.3%. However, short term fuel trim 1 was acting rich(?) while short term fuel trim 2 was acting a little less rich(?) Rich meaning negative value is the ECM pulling fuel.


I have searched the 2007-2014 forum, did not really find much for both P0131 and P0171. Hence my post.
I am writing to see if anyone has any insight?

I am on a crunch because I should have been in bed hours ago. To get up this afternoon to go to work. I have to go to work tonight, and Sunday night. Monday morning, I am off for a week.

My intent right now is this:
-tonight, clear the codes before I drive to work. See what happens.
-Monday and Tuesday, perform the transmission work I had scheduled, because I will be replacing both primary O2 sensors with GM Genuine 2133866 units as part of it. After the transmission adapts are relearned, I will see how the Escalade drives on the way home, and see if the P0131 and P0171 return.
And troubleshoot accordingly.

Thanks for listening!


P.S. I learned in the owner's manual that the remote start will not function if the check engine light is on. Good to know...

 

[swathdiver]

Hello Gentlemen,

Well, the honeymoon is over with my 2013 Escalade ESV Premium. Last night, the check engine light came on. This morning, coming out of work, the remote start didn't work.

Once home, I dug out my neanderthal scanners and pulled codes. I have the following DTC's stored:
P0131 (scanner called it 'O2 sensor circuit low voltage bank 1 sensor 1') Alldata calls it 'HO2S Circuit Low Voltage Bank 1 Sensor 1'

P0171 (scanner called it ' System too lean bank 1') Alldata calls it 'Fuel Trim System Lean Bank 1'


NOTE: I did not 'feel' the check engine light come on. I just happened to look down and see it on. The vehicle drove fine (no different than my limited 5 days of driving) last night and this morning.
Also, this Escalade is a Flex-Fuel model.

I have done some quickie google-fu and general consensus is:
P0131 is likely a failing bank 1 primary O2 sensor
P0171 is likely an air leak.

However...according to Alldata, conditions for setting P0171 include P0131 NOT being set. Meaning two different issues? I had been caught in the 'chicken or egg' mentality. Meaning, was I seeing codes for a failing O2 sensor, or is the O2 sensor reacting properly to an air leak?

I used both scanners to pull some live data at idle. NOTE: I have a clone Tech 2 on order, but it likely won't be here for another week.

FRP(psi) 43.1-43.9
ST FTRM1(%) -0.8 to -2.3
LT FTRM1 (%) 2.3
ST FTRM2 (%) -1.6 to 0.0
LT FTRM2 (%) 2.3
O2S11 (V) 0.100 to 0.750
O2S12 (V) 0.645 to 0.670


Looking at Alldata:
P0131 is set when the HO2S voltage drops below 0.050V. Looking at what I believe are my primary O2 sensors, neither is below 0.100V. However, note how sensor 1 varies while sensor 2 is relatively steady.

P0171 is set when the long fuel trim for bank 1 is greater or less than a calibrated value. I sorta got lost looking at that one. I did note that both long fuel trims were stable at 2.3%. However, short term fuel trim 1 was acting rich(?) while short term fuel trim 2 was acting a little less rich(?) Rich meaning negative value is the ECM pulling fuel.


I have searched the 2007-2014 forum, did not really find much for both P0131 and P0171. Hence my post.
I am writing to see if anyone has any insight?

I am on a crunch because I should have been in bed hours ago. To get up this afternoon to go to work. I have to go to work tonight, and Sunday night. Monday morning, I am off for a week.

My intent right now is this:
-tonight, clear the codes before I drive to work. See what happens.
-Monday and Tuesday, perform the transmission work I had scheduled, because I will be replacing both primary O2 sensors with GM Genuine 2133866 units as part of it. After the transmission adapts are relearned, I will see how the Escalade drives on the way home, and see if the P0131 and P0171 return.
And troubleshoot accordingly.

Thanks for listening!


P.S. I learned in the owner's manual that the remote start will not function if the check engine light is on. Good to know...

Solve for 131 first, it likely caused the other. With the Key on, that sensor should read about 450mv. You can also measure resistance in OHMs on that particular sensor.

Swap upstream sensors. If the problem moves, it's time for a new O2 sensor. If it does not, a mouse is eating your wires or your ECM is bad.

 

[skpyle]

Solve for 131 first, it likely caused the other. With the Key on, that sensor should read about 450mv. You can also measure resistance in OHMs on that particular sensor.

Swap upstream sensors. If the problem moves, it's time for a new O2 sensor. If it does not, a mouse is eating your wires or your ECM is bad.

That makes sense, and dovetails with what I was wondering.
I have modified my plan slightly, I am going to connect the scanner and (safely) watch the HO2S bank 1 sensor voltage as I drive to work tonight.

I have two new sensors, So I am just going to replace them. I will check the voltage and return pins on the sensor plugs at the time.

Thanks! I very much appreciate your advice.

 

[swathdiver]

"...nothing is sailor-proof." GSE1(SW) Pyle

LM2500s and Allison 501s?

 

[skpyle]

LM2500s and Allison 501s?

Oh yeah. LM2500's for main propulsion, and Allison 501K-17's for power generation.

 

[skpyle]

While driving steady state on the highway to work, I was able to sneak peaks at the scanner.
O2S11 varied from 0.000 to 0.750V
O2S12 was steady from 0.735 to 0.740V

This tells me that bank 1 primary O2 sensor is going flaky. It will be replaced.

 

[swathdiver]

While driving steady state on the highway to work, I was able to sneak peaks at the scanner.
O2S11 varied from 0.000 to 0.750V
O2S12 was steady from 0.735 to 0.740V

This tells me that bank 1 primary O2 sensor is going flaky. It will be replaced.

It's supposed to vary once heated up but that is not the only tell all if it has gone bad.

I miss the smells, paint, DMF, JP5, salt air. Spruances, Kidds, Ticos, Arleigh Burkes?

 

[skpyle]

Good point.

Depends upon the day. The longer I’ve been out, the better it was…
Tico class, though trained on the Spru-cans.

 

[wsteele]

The upstream sensors (sensor 1 on both banks) is supposed to switch up and down in voltage when operating properly. If it isn't switching (relatively flat line on the graph), the sensor is bad. The downstream sensors (post cat, sensor 2) will look more like a flat line as they are reporting your cats are working.

Since you are going to swap them with new, you likely will get a pretty good idea if you have one or two problems.

 

[skpyle]

It's supposed to vary once heated up but that is not the only tell all if it has gone bad.

I miss the smells, paint, DMF, JP5, salt air. Spruances, Kidds, Ticos, Arleigh Burkes?