Please help with P0171 and P2195 issues (16 Viewers)

[Hexar]

Hi Guys, First post here.
Here is my situation:
I purchased a second hand 2007 Tundra double cab long bed not too long ago but I did not drive it much.

It developed a problem with the secondary air injection pump, with P2440 code, bank 1 switching valve stuck open. After searching various Toyota forums, I DIY'ed a bypass kit using a regular automotive relay + 4.7k ohm resistor and some wires, and I also put in a bypass plate sandwiched between the switching valve and exhaust pipe.

The P2440 code went away! But I now get P2195+P0171 codes. I don't think I got these 2 codes before the bypass, but I did not drive the truck long to be really 100% for sure.

But in any case, regarding the P0171 and P2195 codes, here are my observations:
1. My LTFT and STFT for bank 1 are: ~30% and ~20% respectively,
2. LTFT and STFT for bank 2 are perfect, change between 0 and ~3%.

So **I think**, maybe my MAF and fuel system are good? Otherwise both banks will be lean, and I would get P0174 code?

I initially thought there is an exhaust leak on bank 1, due to the fact I took apart the SAIS switching valve on bank1, and I honestly did not see a gasket between the valve outlet flange and exhaust pipe flange, so I put on some Permatex Red High-Temperature RTV Gasket Maker between the switching valve flange and pipe flange and tightened them up good.

But after that, I still get P0171 and P2195 codes after 1 hour drive.

I then used Car Scanner app on my Android phone + ELM327 dongle to log AFR O2 voltages on B1S1 and B2S1, and during engine idling, I pressed the brake pedal to simulate a lean condition (this idea is from several Youtube videos).

My O2S5 voltage (Oxygen sensor 5 Wide Range Voltage, I don't know why the software shows sensor 5 voltage instead of sensor 2, but I assume this is the B2S1 AFR sensor, as other sensors are disabled in the software) consistently hovers over ~3.25v during idle, and goes up to 3.4V when I pressed the brake pedal, then goes down to ~3.1V when I release the brake pedal, then it will go back to ~3.25v after it "stabilizes" for several seconds.

My O2S1 voltage (Oxygen Sensor 1 Wide Range Voltage) however consistently hovers over 4.5V during idling, and it shoots up to ~5V after I press the brake pedal, it probably went over 5V as the software recorded a flat line at 5V for several seconds. Then the voltage drops to 4.5V, but it never went below 4.5V (like B2S1 does under 3.25v) and its response seems slower compared to B2S1.

I think my O2S5 (or B2S1) is behaving normal. But my O2S1 (B1S1) is not.

Are there other tests I can do to positively determine the problem is the bad B1S1? As I don't want to spend $180 dollars to replace a non broken AFR sensor.

I am thinking to swap the two AFR sensors from 2 banks, and observe the voltages and potentially trigger a P0174 code? If I get a P0174 after swapping the sensors, then I can positively identify the current B1S1 is broken?

What do you think?

Thanks!

Hexar

 

[Hexar]

My old Mini VCI cable was not able to read Data List nor perform Active Test from TechStream, so I ordered an OpenPort 2.0 cable and it came this weekend.

So today I looked at several sensor readings and did a couple of active tests, including the so called "snap throttle" and Injection volume increase/decrease by 12.5% test from TechStream.

Here are some of the graphs recorded and my observations:

1) this is when I did a series of "snap throttle" tests: rev the engine to ~3000rpm, then release the throttle, then I blipped the throttle for several times.

LT Fuel Trim for S1 is 20%, and I think bank1 has trouble maintaining Lambda close to 1, and B1S1's voltage is consistently high, middle line at 4.2V and many times at 4.99V.

B2S1 seems to be much better.

2) This is another set of snap/throttle tests, and I was trying to observe both upstream and downstream sensors, trying to determine if my Cats are good or not.

B1S1 is again constant at 4.99V, and B2S1 seems normal.

I don't know how to read B1S2/B2S2 numbers, and understand their behaviors.

3) This is when I did several +- 12.5% injection volume tests for AF sensors from TechStream.

I was experimenting with Active Tests (first time) and observing the graph at the same time, so I don't remember how many times I tested and if I blipped the throttle in between the Active Tests or not.

But I can see B1S1 does not react to the injection volume up and down at all.

Odd is: fuel trim for both short term and long term came down to 0% for some reason? maybe communication problems?

4). This is when I decided I need to do exactly two volume up and two volume down Active Tests: +12.5%, -12.5%, +12.5%, -12.5%

It seems B1S1 reacts to the injection volume change, but not much? (the X time scale is short, and I adjusted Y axis range making the graph easier to read.)

And the B1S1 voltage is still very high, hover around 4.9V range, even the low readings are above 4.93V.

So what do you guys think? Is B1S1 bad for sure?

What other tests can I do?

Thanks!
Hex