george42

Hello Fellow Members,

I need your help for this one,
This is going to be a rather lengthy post, so be prepared lol.

I've recently had a couple of CELs with my 2010 IS250 AWD.

It began a while back with a couple of errors stating "catalyst efficiency below threshold bank 1"
I can't remember the code, but I cleared it to see if it would come back. (I have a picture of the failed test and Graphs that caused the CEL below)
After clearing the code, it never came back in over 3 months, and O2 Tests after that were always a PASS, so I'm not sure what that meant.

Then around 2 weeks ago, I recently had a bad battery that I believe caused my other codes, (Again, Picture Posted Below
P0340 Crank Position Sensor
P0172 Bank 1 Rich
P0175 Bank 2 Rich
After getting a new battery (It was old, and -40c outside), the codes went and didn't come for over 2 weeks
Kinda figured it was the low battery voltage that was causing the erroneous codes; after all, they never came back...

Now that my car has been running fine for over 2 weeks, I've had the CEL come on again, this time with only one code.
P0172 P0172 Bank 1 Rich

I was sure to take lots of data and snippets to see what was wrong this time, and I will attach them below.
I'm sure the car is indeed running rich, as when the car does cold starts (Canada, eh?)
You can hear popping noises from the exhaust (The car has an Axle-Back, so it is more noticeable)

I think it's an O2 Sensor in Bank 1.
Probable cause of the initial Catalyst Efficiency code, which was also on Bank 1?
The only thing is, the car still says the O2 Sensor Tests passed, with the real-time voltage still good.

Is this a periodic issue?
Also, While reading data I noticed I'm having a Long Term Fuel Trim of -32% on Bank1 and -27% on Bank 2,
Should I concerned, or is this due to the O2 sensor?

Your Inside would be greatly appreciated!

1st Time CEL

1st Time CEL

2nd Time CEL (Dead Battery)

Current Tests (3rd Time CEL)

3rd Time CEL Graph

3rd Time CEL Live Data 1

3rd Time CEL Live Data 2

Should I be Concerned?


Thank you very much!

firestart9

I had the same P0172 code a month ago and it went away, then returned. I don't have a legit OBD reader so I'm gonna read all the replies to this thread. My plan is not to do anything tho cos I didn't notice any major increase in fuel usage. Code is also gone and hasn't returned in warmer weather (in Canada).

MikeFig82

iTrader: (13)

From the data I scanned. The only thing that stands out is the MAF reading. On a fully warned up engine it should rear near engine displacement. Which for the IS250 is around 2.5 g/s.

Have you tried cleaning the MAF?

george42

Thank you very much for taking the time!

Yes, I just cleaned the MAF Sensor and reset the ECU by unplugging the battery.
I haven't checked the values yet, but even though the car doesn't have a light anymore since I unplugged it, I can say I feel a slight hesitation when it shifts down.

Most of the values posted above would be when the cars semi warm, since I'm in Canada it takes a very long time for the cars to warm up, especially this car for some reason. Probably because of how much coolant and oil it takes for such a small displacement.

With that being said, I took a closer look at the data and saw:
O2 B1S2;
Ranges from 0.115V-0.855V

While O2 B2S2 floats around:
0.095V-0.135V

And during this time, all the Upstream A/F Sensors stay around:
1.003-1.008 Lambda
3.324V-3.416V

Would it be safe to say its the O2 B1S2 Sensor misreading?

george42

Well, I'm also in Canada.

While my car died and gave several codes including P0172 and P0175 during the cold snap, I think it was partly due to the old battery, however, my Bank 1 O2 sensor was reading 0.855V when the other side was reading 0.135V like it was in warmer weather.

Aside from a possible dirty MAF which I cleaned, I suspect my Bank 1 Sensor is going, and will have to be replaced.
For reference to your car, mine has 224,000 km, so it was probably time anyway.

MikeFig82

iTrader: (13)

While the car is on. Pull a vacuum hose to induce a leak. What do the Fuel trims do?

Do the long terms start shifting positive quickly?

Here's a video to help out. It seems you have Techstreme as well.