jagtoes

So if you now clear the codes and start it up and maybe drive it what is the 1st code to come up. That would be your 1st place to check.

ThumperPup

in the past 2-3 weeks 4 times since i have had my car back and been driving the 07 ES350 i have had the P0420 code come up i clear it once it came back after 1000 miles and 3 time sit came back between 70 and 200 miles

I was just looking i checked with the lexus dealer a cat convertair for the right side which pertains to this code firewall side conveter
the lexus dealer wants like 1000 for the right side eqsuaste manifold with converter for my 3.5 engine in the 07 ES350
however if i where to get one from the toyota dealership for a 07 avalon or Camry with the 3.5 l it would be like 700 dollars
will one from a 07 Toyota Camry with the 3.5 l engine be the same exactly bolt on as the one for the 07 ES350 that i woudl get form the Dealership ?

nevernu

P0420
OSC value is smaller than standard value under active air-fuel ratio control (2 trip detection logic) possible causes
z Gas leakage from exhaust system
z A/F sensor (bank 1 sensor 1)
z HO2 sensor (bank 1 sensor 2)
z Exhaust manifold (TWC)
Maybe its just a sensor

ThumperPup

thankyou for this
i hope that it is just a sensor but how do i find out what sensor it is wouldn't their be another code for the sensor itself ?
the only codes that come up each time is the p0420 code no other codes have come up.
wouldn't these sensors have codes of their own ?

ThumperPup

If it was an oxygen sensor or the AF sensor wouldn't their be a code specifically for that?
How can it be tested on weather its the esuastmanfold leaking or if it the Cat that is bad?

ThumperPup

i am confused on how to find out what exactly it is that is wrong.
I have read some stuff
I don't have any burning smell or smells or noise coming from the engine no fumes smelt nor loose of power or performance that i can tell.

so i don't think that i have a leaking manifold or cracked exhaust system because there is no tell of those signs

nevernu

I have no information to offer other than the P0420 code includes possible AF/HO2 sensor problems even if no other DTC codes are thrown.. If you follow the troubleshooting chain in the pdf file I attached, they use Techstream and work their way through, eliminating/zooming in on faults. I would suggest you ask the dealer to run the Techstream diagnostics to see where they end up. The diagnostic cost is surely less than blindly replacing stuff.

ThumperPup

On Bank 1 the sensor that is upstream is the Air Fuel Ratio Sensor that would be sensor 1 right side before the cat and sensor 2 would be right side downstream which is the heated oxygen sensor is that correct ? or do i have this mixed up ?

nevernu

check this out

ThumperPup

thank you
so looking at the pictures it looks like their are 2 sensors on each bank from the last picture it seems as if i am thinking correclty that upstream sensor 1 is the A/F Sensor
and Downstream Sensor 2 is the H02 Sensor for bank 1

ThumperPup

I went to the Dealership today, and they looked it over they told me that they don't see or find any evidence of a leak in the system from the manifold gaskets or anything like that, and they don't have anything telling them out of the steps they followed nothing to show that its a sensor that is bad
I trust this dealership the service tech always does good to me doesn't try and sell me things that I don't need I have gone in in the past for second opinions after shops have told me I need mounts or axles replaced and he has told me several times when I have had other shops tell me I have issues that those issues don't' exist so I trust him when he says if it were his car he would start with replacing the Manifold and Cat for bank 1

So I ended up ordering a Manifold right side bank one I got it online from Lexus in Warwick RI they sell Lexus parts wholesale prices I paid 633 after taxes and shipping for an OEM right side bank 1

nevernu

Hope that resolves it, I trust my dealer as well for the "Lexus" stuff

ThumperPup

So today the Cat manifold right side that i ordered came from lexus on RI
when i opend the box their where 2 other items in their of parts that i didn't order
8946733180
8946733170

did they just box these by accident or do the A/F rat sensors come with the manifold?
Also, i notice these are both A/F sensors for RH and Left side did the dealer just screw up and package extra items by accident?

PoorES

I think they come with them. Otherwise, legally, you have every right to keep them. Just install them and be happy.

ThumperPup

i called to find out today first the manager said no those must have been sent by mistake then he called me back like 10 minutes later said he went and looked at the other exhaust manifold stock he had and all the boxes had those sensors in them so he did some digging and found that a New Exhaust manifold from Lexus also comes with both sensors
so now im even more happy that i spent the money on the OEM because those sensors alone are like 170 or 200 each new OEM i think
so 633 after shipping for a manifold cat and both sensors