Driven 5k+ miles on code P0133 & P0155; causes & issues

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2001LC

2001LC

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I'm buying an over 200K 00 LX470, T-Belt/wp, valve cover and spark plug tube seals done ~3.5k miles ago. Shop reported CEL was on pre T-belt. Nothing was done to correct, and CEL was cleared at that time. P0133 & P0155 codes indicate Bank 1 & 2 Sensor 1 (forward o2's)

I'll see it for first time today.

I've now learn why CEL is on, reportedly it came on a few weeks ago.

What are some of the possible issues that would cause these o2's to go bad?

What damage may have been done driving for 5k miles or even more with these codes?
 
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If the code is p0113 then this could be the cause of the O2 sensor and knock sensor codes as this info will be used for air/fuel ratio, it is linked to ignition timing and emission controls.
 
I'm not sure where it is in the FSM as I don't own one, p0113 code is air temp circuit high, so it has seen 5v for some reason, this is part of the MAF sensor, so have a look to see if you can see any damage inside as they are easily broken, check the air filter also.

If the engine runs good from cold but then starts to splutter when warmed up abit then this is a classic sign of a faulty 02 sensor as the info from the 02 sensors are ignored during the cold start strategy. So if it runs rough from cold then this would lead me to think that the issue is elsewhere.

As for damage, it would be the CATs that could get damaged, but if the downstream oxy sensors aren't bringing up a code then they seem to be OK.
 
I just spoke with shop and P0133 & P0155 is all they saw and they did not run diagnostic tree. I've gone back too OP and edited out the P0113 stuff..

Good info on cold & after start up, thanks.

Cat & ECU is concerning, as Dealer quote $2k ea & $1,100.

o2 can just fail I suppose, but can also be caused by fuel air mixture issue up stream. If up stream fuel/air mixture shouldn't this be indicated by other codes first. In this case should I see additional codes or is bad o2 most likely?

And if cat's bad shouldn't I now get codes or does front o2 issue need correcting first to get down stream code?
 
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Yes, the most common problem would be just the O2 sensors, they just turn bad with age. The downstream oxy sensors should pull up a code regardless of the upstream sensors if the CATs where faulty, so if there's no codes then they should be good.

I wouldn't of thought the ECU to be faulty unless there is a known fault regarding this, as I would of thought there would be a different code regarding open circuit or a short circuit code.

The previous owner doesn't sound like he looked after truck much though as he/she put a aftermarket timing belt on which is false economy due to the labour required to carry out the job, then also driving around with O2 sensors faulty for 5k miles, for such a relatively cheap repair its mad, sounds like it was more of a workhorse than a family runaround so a good check over and a glance at the service history required I think.
 
We were on vacation last summer when the CEL went on. I forget what was the code, but it was for front O2 sensor DS. Stopped at local Auto zone store that we happened to pass by, but they did not have the O2 sensor. The older gent that works there said that should be ok to drive a bit without changing it. I didnt really feel like looking around for O2 sensor while on vacation anyway. Drove the car all the way back home before changing O2 sensor ~1.5K miles later. So far everything works fine.
 
I found Mickey's winter home in the air box. Either that or a Lexus pre filter...;)
 
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So to recap; In 2014 A**** Auto Clinic read CEL P0133 & P0155 as #1 o2's. Tech's note recommends all o2's and the knock sensor be replaced. I have no idea why they recommended knock sensor at that time. They only cleared CEL, and no repairs to correct was performed in 2014. Two weeks ago CEL returned, throwing P0155 & P0325 codes, o2 #1 bank 2 & knock sensors #1 bank 1 this time.

Mickey Mouse's winter home, without doubt reduced airflow. This may have been Mickey's second stay, but no "check-in ledger" to confirm. So strong possibility sensor(s) may be ok. I cleaned air box of several cups of food.

Interesting in 2014 owner took in to A**** Auto Clinic because of CEL, said fix it. Under the impression that the $2,700 bill he paid, was at least in part to fix cause of CEL issue. A**** Auto Clinic said they did not run diagnostic only read and cleared codes. I wonder why they did T-belt???

2014 tech notes at end of $2,700 bill: Recommend; Replace all o2's & knock sensors. Rear shocks leaking badly, recommended change all four due to age (they were wrong Shock are good). Tune-up soon to included spark plugs, fuel filter and fuel induction service. Tech found codes P0133 & P0155 heated oxygen sensor failure and knock sensor failure, suggested replacing both knock and all oxygen sensors.

It's been like pulling teeth to get info from A**** Auto Clinic on phone. So yesterday owner and I took back too get printout of 2014 repairs and get codes read. ~90 minutes after arrival we were back on road. Turns out they inspected as part of the free code reading for "Safety reasons". In this "inspection" they gave us the above codes recommending one o2 & knock sensor or single sensor be replaced. Additionally notes stated: Suspension fluid is low (I noticed ~1/2 inch below low line). Engine air filter dirty (They replaced 3,500 miles ago, that's mickey at work). Power steering return line leak. Power steering flush - dirty. Radius arm bushing - minor cracking (AKA rear control arm bushing). Oil pan seepage - slight.

Now what is really interesting is that, none of the 2014 recommended work was every done. Yet this inspection tech notes made no mention of badly leaking shocks or other stuff for past inspection. Maybe Mickey fix it all, he is magical isn't he?
 
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Oh, I do now believe CEL only came back on recently. So this LX will only have been driven a few hundred miles at most with CEL on.
 
Good advise. Pulled the engine cover during inspection, to better hear sounds. listened to vacuum hiss change as I wiggled PCV. Needs R&R w/ new grommet & hose for sure. May need to clean and torque a few pan bolts and such.

I'm thinking engine and transmission need a good baseline tune. I'm betting all is good from their. Wondering if CEL will clear on its' own, or do I need to have cleared?
 
If you have a fault code reader I would clear them, they do clear themselves after so many good cycles but not sure how many. Good idea to baseline, hopefully the spark plugs don't give you to much grief, mine did and took much longer than I would of liked, if they are tight coming out patience and care is required.
 
I don't have read, never had a code in my 01 LC. I could pick one up or just have Parts store clear. Does clearing remove from all memory permanently?
 
I'd pick up a code reader. They are cheap, easy to use, and ought to be in the toolbox. I use a Scangauge II mounted in my console and plugged in all the time, but even the less expensive temporary ones remove all codes from the ECU.
 
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