ArmyofOne

Ok, so at present, I have the above codes. I have replaced the rear bank upper O2 sensor twice. It's at Lexus now. They are diagnosing. I am in between homes now (sold mine, waiting for my new one to be finished and staying with family in the interim) and in the meantime, I can't work on or diagnose much of anything. All of my tools, except my code reader and a few basic hand tools are in storage. So, looks like I get to take a reaming on this one. I will let you know what they find. They did call me a bit ago to ask me if they could do a smoke test to find the evap leak, and that best case scenario that was a gas cap (i knew that already) but worst case scenario that was a charcoal canister ($700), ouch. Also that if I changed Bank 2 Sensor 1 and I changed the sensor against the firewall, then I changed the wrong sensor, and that bank 2 sensor 1 is the one closest to the radiator. Doesn't matter because I changed them both, once with walker sensors, and once with denso sensors, so there must be something else going on.

I will report back with the findings...but this has the potential to be a painful repair.

nsghtbrwry

Whoo, what a doozy. Looking forward to hearing more as the situation progresses.

semlin

assuming you installed it properly, i'd replace that o2 sensor. it looks to be bad out of the box to me. did you try putting the old one back to see if threw the same codes?

ArmyofOne

Installed it properly?

You can't install it incorrectly. I have been a mechanic for 15 years. There is only one way to install an O2...and thats the same way the old one came out.

I have replaced that O2 sensor, twice. Once with an aftermarket, and once with an OEM. and I replaced the front one twice, once with an aftermarket and once with an OEM. The odds of getting 4 bad sensors out of the box new, from 4 different suppliers, at 4 different times? No, not a chance.

There is something else wrong with the car. Either it has a faulty injector, or there is a vacuum leak somewhere...I am not sure. But that's why its at Lexus. They will narrow it down. If I had access to my software system, my new garage all set up and my tools in it, then it wouldn't be there, but it is what it is.

crwys

The only thing I can add is that when it comes to sensors in these cars, is to stick with OEM. Which is usually denso.

nsghtbrwry

Hm, I'm working on an RX with a persistent P0302. It'll be fine for a week or two, then pop up and drop into limp mode. I just replaced knock sensors due to a P0330, and its running fine otherwise. I told the guy to replace the battery, as it had leaked and there was copper sulfate all over the positive terminal (also to take apart the terminals and clean everything).

Several months ago, I had a RAV4 in that would constantly throw O2 sensor and lean codes. No vacuum leaks, and O2 sensor had been replaced with a Denso (forgot to mention, this is a 4cyl 2000). Turned out the battery was the 17-year-old original one! Also the previous mechanic had mangled the positive terminal. Replaced positive terminal, cleaned all cables, replaced battery, and it ran like a champ with no codes.

What I'm getting at is, these cars behave wonky when there's high resistance in the battery/charging circuit...how're your battery, terminals/cables, and grounds?

ArmyofOne

Battery is from 2013, terminals look decent, a little dirty but not corroded, and the grounds that I have seen in passing all look ok. I am in TX and this has been a TX car, so corroded grounds aren't much of an issue here, but nonetheless, its something I will have the technician check if he calls me and he is stupefied. However, I am confident Lexus knows what they are doing with the car and can pinpoint it. At this point I haven't the time, nor the space or tools to work on it. It would literally require me to work on the car on ramps on the side of a street where people drive at 45 mph (speed limit is 25 but people are retarded). Not ideal. Not only that but the HOA prohibits working on vehicles outside of your garage here. The household where I am staying has 3 cars already, their 3 car garage has no driveway and comes out to an alleyway which is a thoroughfare for everyone on the street to access their garages. My 3 cars usually park on the street out front.

Its not an ideal situation, but it is only for a 2 month stretch. We "moved in" September 2nd and our new house will be completed October 30th. We can handle 60-ish days of musical parking.

nsghtbrwry

I hear you. I'd never buy a house in a neighborhood with an HOA, but my neighbors are just as bad. The city's harassing me about my project in my own driveway because of one busybody PoS. In any case, looking forward to hearing the solution.

semlin

i didn't understand your original post meant you had tried two sets of o2 sensors. i have failed to plug in an o2 sensor properly before, and i can envisage not installing it properly in the boss and getting an air leak.

going on the theory there are no coincidences, the evap code points me to an air leak in the fuel system on bank 2 interfering with the injectors getting enough fuel. good luck with the cure.

ArmyofOne

ok, Evap code was a brittle vac line. going to see if that fixes the problem.

EDIT: Picked the car up this morning. I will reserve judgement for the time being, but it seems to be fixed. I will report back in a week if the codes have not returned.

ArmyofOne

No worries bud, its the internet, things happen. Yes, this car has now had 4 air/fuel (upper) sensors, 1 aftermarket crap sensor and 1 Denso in bank 1, and 1 aftermarket crap sensor and 1 Denso in bank 2,

Turns out, you were (seemingly) correct! A vacuum leak on one of the fuel rail vacuum lines. I missed a brittle/cracking line when I was replacing them, and that was the culprit. So for $42.50, I am back on the road.

Total tally:

-MAF Sensor: $35
-Aftermarket Air/Fuel Sensor bank 1: $55
-Aftermarket Air/Fuel Sensor bank 2: $75
-Replacement 3/8 Vacuum hose (6 ft): $10
-Throttle Body Screen/Gasket (whatever it was a few bucks): $5
-Front Valve Cover Gasket (weeping a bit, might as well while i was in there): $35 for front and rear
-Intake Manifold Gasket set: $33
-Denso Air/Fuel Sensor Bank 1: $120
-Denso Air/Fuel Sensor Bank 2: $155
-PCV Valve: $5
-Denso Iridium Plugs: $35
-Denso Ignition Coils: $95 for the set of 6.

Grand total: $658. Add the $42.50 from today and the grand total comes to a whopping $700.50. Remember, all but the $42.50 charge from today, I did myself.

I have owned this car since February 20th. Average that out, it's cost me $100 a month to own it, if you don't count oil changes, gas, and insurance (which I don't because thats required for every car).

Now, in reality, this car needed 2 items at this time to fix the CEL. It needed:

-Denso Air/Fuel Sensor Bank 1: $120

and all the vacuum lines replaced. So...

-Replacement 3/8 Vacuum hose (6 ft): $10

I chose to do the rest of it as preventative maintenance. What I didn't choose to do was install 2 bad air/fuel sensors from an aftermarket supplier, causing my car to go absolutely haywire.

So, in reality, the math goes more like this: $120+$10+$42.50=$172.50/7=$24.65 per month to own. Not too bad for a 15 year old entry-level Luxury car.

semlin

glad you got it sorted. i generally end up using dealers or throwing parts at the problem in winter when it is too cold. it rarely goes well for me.

ArmyofOne

So far, the CEL has not returned.

I am not confident the problem is sorted. This time next week if it hasn't returned, I will relax a little. I can say that the symptoms seem to be gone. However, they seem to go away every time you clear the codes, they stay away for awhile, then the codes come back. So we'll see.

ArmyofOne

20 miles yesterday. 60 miles today. No issues yet.

ArmyofOne

ok, It is now Monday, mid afternoon, and 200 miles later. Repeated highway trips in the car and no CEL.