Holy DTC code hell!!! 2008 Limited

*** got a data log finally ***

We hooked up the torque app using my android phone and found out that her Bank 1 sensor 1 and Bank 2 sensor 1 are not working. Check out the screen shot below. The fuel trims are reacting accordingly as well.

In my '03 V8, my B1S1 & B2S1 are showing normal values so I'm not sure what's going on with her B1S1 & B2S1. The sensor 2 values from both banks are operating in her vehicle.

If this is indeed the case, then I'll need to find a connector that's common to both O2 sensors. I can't imagine both O2 sensors going belly up at the same time.

Let me know your thoughts.

Thanks.
 

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that seems more like a software issue than a vehicle issue, even though it works fine in your truck. if they were not working like pictured you would have numerous codes.
 
my next suggestion would be to buy a back pressure gauge and test both banks, the gauges are inexpensive and thread right into the 02 sensor ports. its possible you have a cat that is intermittently clogging the exhaust. I haven't ever seen that before but it would cause most of your issues aswell as lots of weird codes.
 
my next suggestion would be to buy a back pressure gauge and test both banks, the gauges are inexpensive and thread right into the 02 sensor ports. its possible you have a cat that is intermittently clogging the exhaust. I haven't ever seen that before but it would cause most of your issues aswell as lots of weird codes.

I've seen plugged cats keep cars from running altogether. If it's been misfiring for a while chances are it dumped so much fuel into the exhaust that it burned the cat up and clogged it. Simply take out both of your upstream O2 sensors to let the exhaust breathe easier and fire it up.. It'll be loud but it should stay running for at least a little bit. And at that point it should run better the warmer it gets.
I'm assuming you've already checked for vacuum leaks and cleaned the mass airflow sensor.
Sorry, running to work so I didn't have time to read through the thread.
 
Clogged cats on a 80,000 miles, interesting. If this is the case, the issue should be consistent. This issue seems random and throws a code unpredictably. I'll measure the cat temp with an IR gun to verify.
 
Clogged cats on a 80,000 miles, interesting. If this is the case, the issue should be consistent. This issue seems random and throws a code unpredictably. I'll measure the cat temp with an IR gun to verify.

ive seen clogged cats under 50k before on various vehicles, its also 7-8 years old. And while yes usually that doesn't create an intermittent issue, checking backpressure is a easy test and provides solid data. you already have a p0430 (bank 2 cat. efficiency) which is a cat code so you potentially have a bad cat already.
 
Did you guys ever pick up a cheap TIS TechStream?

It seems odd that both Bank 1 Sensors are not out putting ANY data... I suppose it's possible, but it seems odd.

First thing I would do is rule out that the Torque App isn't having an issue (maybe shoot the dev an email.) If the issue isn't with the scantool's protocol then we can assume there might be an issue with the sensors and go from there.
 
Did you guys ever pick up a cheap TIS TechStream?

It seems odd that both Bank 1 Sensors are not out putting ANY data... I suppose it's possible, but it seems odd.

First thing I would do is rule out that the Torque App isn't having an issue (maybe shoot the dev an email.) If the issue isn't with the scantool's protocol then we can assume there might be an issue with the sensors and go from there.

We ran it both in my troublesome 08 and Ali's perfect 03. It work just fine in his vehicle...... Only one sensor bank works in mine. :whoo:
 
*** update with data log during engine meltdown ****

well, we FINALLY captured the data during the engine having a flat out meltdown yesterday evening.

Symptoms:
- sputtering, missing, backfiring
- in Neutral, engine can't go to high rpms
- in Drive, if you floored it, total bog down and eventual shut down
- after turning ignition off then back on, I could rev the engine rpm freely, goes all the way to redline. But in Drive with brakes on, if I floored it, massive backfire, cough, all kinds of fault lights come on.

Sat in the garage overnight and today, she drives like a normal vehicle with zero hints of issues.

Torque app showed the engine going between open loop and closed loop while this was happening. Still can't figure out why there is no voltage for both O2 sensor #1 out of both banks. Sensor #2 out of both banks reporting normal voltage, or at least some activity.

My first plan of attack is to swap out all four O2 sensors with used ones from the shelf. These came out of my 80 series Land Cruiser so they should be compatible, including the connectors.

I could also swap out the cat pipes from my '03 sport V8 and see if the problem follows the cats. However, I hesitate to blame the cats due to the fact that unburned fuel is getting dumped into the cat and they're simply burning it as they're designed to do. One thing I'm going to do is for both of our vehicles to make the same trip and then compare the cat temps with a IR gun.
 

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well, we FINALLY captured the data during the engine having a flat out meltdown yesterday evening.

Symptoms:
- sputtering, missing, backfiring
- in Neutral, engine can't go to high rpms
- in Drive, if you floored it, total bog down and eventual shut down
- after turning ignition off then back on, I could rev the engine rpm freely, goes all the way to redline. But in Drive with brakes on, if I floored it, massive backfire, cough, all kinds of fault lights come on.

Sat in the garage overnight and today, she drives like a normal vehicle with zero hints of issues.

Torque app showed the engine going between open loop and closed loop while this was happening. Still can't figure out why there is no voltage for both O2 sensor #1 out of both banks. Sensor #2 out of both banks reporting normal voltage, or at least some activity.

My first plan of attack is to swap out all four O2 sensors with used ones from the shelf. These came out of my 80 series Land Cruiser so they should be compatible, including the connectors.

I could also swap out the cat pipes from my '03 sport V8 and see if the problem follows the cats. However, I hesitate to blame the cats due to the fact that unburned fuel is getting dumped into the cat and they're simply burning it as they're designed to do. One thing I'm going to do is for both of our vehicles to make the same trip and then compare the cat temps with a IR gun.

First thing that jumps out as WTF is the baro pressure. Check that with the other truck to figure out what it should be. if its way off, then that will most certainly cause your issues. Around here ( close to sea level +- a few hundered feet) its usually around 145-150 depending on the day/weather
 
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[TL: DR at the bottom]

So the thing is that there is no "Barometric Pressure Sensor," in fact there isn't even a Barometric Pressure PID for this vehicle, the FSM lists a "Atmosphere Pressure" PID under the Data List/Active Tests section; that data is pulled from the "Atmosphere Pressure Sensor." I would email the scantool manufacturer and verify that their scantool is most likely converting the "Atmosphere Pressure" PID into "Barometric Pressure."

In the meantime, lets go ahead and run with the assumption that the data value is accurate and the name has simply been changed from "Atmosphere Pressure" to "Barometric Pressure" (for the rest of the post I will be referring to the measurement as "Atmosphere Pressure.) Now this is where things get a bit interesting...

80kpa is the value we see consistently output by the Data List you posted, that strikes me immediately as an odd number because normal atmospheric pressure is considered 101kpa (14.7psi), this implies that the Atmosphere Pressure Sensor is seeing a vacuum (about 6.3inHg of vacuum when you convert it.) So the next question is where the hell is this pressure sensor and what is it supposed to be reading?

Well, it turns out that the only Atmosphere Pressure Sensor is located on the Air Switching Valve located under the intake manifold in the valley on 2005~2009 2UZ-FE equipped 4Runners.

A134408E03.png

This sensor is watching the pressure from the switching valve to determine whether or not the pump and switching valve is functioning correctly. To simplify the explanation here (because there's no reason to delve too deep into how the monitor works right now), it's watching for fluctuations in pressure and pulsation in pressure as it operates the valve and pump to verify that it is in fact operating correctly when commanded. According to the FSM, the "normal range" for the sensor is 0kpa to 150kpa (or from perfect vacuum to 7.2psi over atmosphere,) there is a DTC P2431 [Secondary Air Injection System Air Flow / Pressure Sensor Circuit Range / Performance Bank 1] can set if pressure goes below 45kPa or higher than 135kPa. But since the sensor is seeing a consistent 80kpa, it wont set the only DTC related to the actual pressure sensor reading. Now that we understand the purpose and function of the Atmosphere Pressure Sensor, we should look at how the Secondary Air Injection System is set-up.

Sec8.png

If you look at the above diagram you'll see that the Air Pump feeds air into the Air Switching Valve which then routes that air to both No.2 Air Switching Valves, which ultimately feeds into the exhaust manifolds at the manifold (before the Catalyst, AFR sensor, and O2 Sensor.)

Now by this point you're probably scratching your head like I am, which is fine; because it is very weird when you break it down this far. While air being injected before the catalyst and AFR sensors could confuse the vehicle into thinking it's running far too lean, leading the ECM to enrich the fuel mixture way too much and possibly cause it to bog down; I personally don't see how that could be happening since, if anything one would expect to see pressure (not vacuum) in the manifold and up to the exhaust ports of the No.2 Air Switching Valves. But the Atmosphere Pressure Sensor is seeing a slight vacuum, which means that there has to be a small leak of some kind after the sensor pulling a vacuum (this is because the Air Switching Valve is after the Atmosphere Pressure Sensor, possibly implying that the valve is not sealing correctly.)

So we have a vacuum in a system that should be seeing pressure if the Air Switching Valve and No.2 Air Switching Valves were leaking since exhaust pressure from the exhaust ports would shove pressure back up the lines. To me this implies that the only possible way for there to be a vacuum is that one or more of the membranes in the vacuum operated No.2 Air Switching Valves has failed as well as the Air Switching Valve is not sealing correctly. This would allow unmetered air to bypass the MAF and go into the intake manifold (of course, this also assumes that the vacuum switching valves at the manifold are leaking as well since they control the flow of vacuum to the No.2 Air Switching Valves) and cause the vehicle to run; but at only about 6inHg of Vacuum... that seems highly unlikely. Not to mention that you'd need at least 3 valves to be incorrectly sealing and even then I am not sure if the volume of air would be sufficient enough for the engine to have any serious drivability issues above idle to begin with.

TL: DR

Basically, while 80kpa seems like a very odd number (particularly how consistent it is); I cannot for the life of me understand how that sensor is reading a slight vacuum or how that would impact the engine in any real way... So I think that's a dead end.

Post Note-

...
My first plan of attack is to swap out all four O2 sensors with used ones from the shelf. These came out of my 80 series Land Cruiser so they should be compatible, including the connectors.

I could also swap out the cat pipes from my '03 sport V8 and see if the problem follows the cats. However, I hesitate to blame the cats due to the fact that unburned fuel is getting dumped into the cat and they're simply burning it as they're designed to do. One thing I'm going to do is for both of our vehicles to make the same trip and then compare the cat temps with a IR gun.

I forgot to mention, that your idea of swapping the Oxygen sensors from your LC80 won't work (I didn't think LC80's even came with a 2UZ-FE?) as the sensors are far too old in design (internal resistance of the oxygen sensors are probably different and I don't recall any of the LC80 engines ever having AFR sensors,) despite the connectors being similar. You may be able to swap your 2003's sensors with hers, I'm not sure off the top of my head.

Something else to mention is that I really suggest you get a cheap TIS Technstream cable; the Torque app is just not outputting enough information and some of it seems like it may not be accurately translating. For example, I would have liked to see the following in that chart :

-Short Term & Long Term Fuel Trims (yours only shows fuel trim in a percentage which is a very odd way to represent that...)
-Sensor Voltages
-Engine Coolant Temperature
-TPS Angle
-AFR Impedance (this is helpful for ruling out bad Air Fuel Ratio sensors)
-DTC Count (Basically this tells you if a DTC set, so you can get an idea where in the data the ECM saw a problem)
-Ignition Timing
-VVTi data (commanded angle, actual angle, ect.)
-Fuel Injector Pulse Width
-ect.

There's a ton of ancillary information that would be worth looking at before, during, and after the event occurs that we're missing here; not to mention that it's starting to look more and more like your scantool is not correctly representing data. I'd recommend getting one of those Chinese TIS Techstream Mini VCI, they're only like $20~30 and should work fine on most laptops, it's basically a bootleg factory scantool.

Update

I just realized something (rather embarrassing it didn't occur to me earlier now that I think about it), the vehicle is probably going into "Fail Safe" mode and that's why it's bogging down and when you cycle the key it kind of works fine. Does it feel like it's not shifting above 2nd gear when this happens by any chance?
 

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Thank you so very much for the education, you know how to break complicated things down well. Wish I had professors like you when I went to engineering school!!!

I agree, we need more data and I'll get the software you suggested. Swapping O2 sensors between our two V8s is going to be a PITA from what I saw.

I'll ask Jessica to respond to your 1st gear question as in not sure!
 
Thanks for the info Blackworks Inc.

the issue with my 4Runner is now happening nearly everyday. when it first started with this issue it was about every 2-3 weeks. The last 12 hours have been especially "joyful".
I am not sure if it is getting stuck in 2nd gear. maybe 1st gear? I was able to limp it home last night and limp it to work this morning. I usually do not have many issues in the mornings....
I have a simple OBD code reader plugged in. I get the same codes P0171 and p0174. I either get them together or single.
I have noticed more backfiring when it is having it's tantrum. always under load. I noticed if the RPMs reached 3K the engine cut out and would 'coast' until the RPMs were under 1K-5oo then I could get a response from the engine to pick up speed. always lurching.
It did die once this morning and once last night. Both times I was able to restart and keep moving. It feels like I am running out of gas. that is exactly what it reminds me of.

I am not sure why it is now a daily issue.... I know Ali has ordered some software to read more engine info.... Hopefully more data will point to the actual issue.

Sigh.
 
TIS Techstream has been ordered and it can't get to me soon enough!

This vehicle is no longer safe to drive so she'll be using one of my vehicles to get around. :nono:
 
**** update ****

I got VCI Techstream loaded and running. Please see the attached screen shots from Techstream. It seems that I'm unable to connect to the Engine ECU so I have no data to report :frusty:

Anyway, the ABS ECU is reporting tons of DTCs, not sure what to make of it. I'm not sure why the engine ECU is not talking to the software. Just for the hell of it, I connected Techstream to my '03 and the engine ECU was behaving normally so it's not a software/cable issue.

I can send anyone the Techstream file if you want to see what I'm seeing offline. Just shoot me a PM with your email addy.

Thanks for any help!!!
 

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I think I had trouble with a few of the different versions of techstream that came on the disk with the cable. I want to say that I was able to connect using techstream version 8. Might want to try that and see what happens.
 
Try it with the vehicle running and see if it will connect. You will not do any damage, so don't fret.
 
I think I had trouble with a few of the different versions of techstream that came on the disk with the cable. I want to say that I was able to connect using techstream version 8. Might want to try that and see what happens.

This doesn't make sense - why would the software connect to all but one ECU? It connected to all the ECUs on my '03. In your case, were you not able to connect at all or partial connection like me? I'm thinking this is a case of all or nothing. Puzzled!

Try it with the vehicle running and see if it will connect. You will not do any damage, so don't fret.

The engine was running when I connected. Trust me on that one, bun warmers were on high and so was the heat. It was 27deg outside, LOL!!!

Thanks for the inputs.

PS. Her '08 has MORE ECUs than my '03, wow doggie! I am thinking that I can really muck up some her settings - like the horn honking, key in the ignition ding dong thing.....This is a powerful tool for sure!
 
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