O2 sensor problem
 

My coworkers 1990 Camry CE has popped a couple of engine codes

P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P1135 Manufacture's code

My guess is a bad O2 sensor is causing all of them, though I am unsure about the P1135.

Where are the O2 sensor locations and does anyone know how to go about removing them. Also which one would the Bank 1 Sensor 2 be? I have read up a tiny bit on what I could find and it sounds like there is one sensor right before the cat and one upstream, I am guessing this is the one right before the cat (or has my information been incorect and it is actually right after the cat?)?

Lastly anyone know the tools and difficulty to replace it (as in can it be replaced without jacks/stands)?

Since I have a fairly vast mechanical knowledge (though no experience working on Toyotas. Only Saturns, Hondas, and Mazdas) I offered to do a parking lot replacement of the sensor for my coworker so he doesn't have to spend a couple of hundred to have the dealership replace it, and I want as minimal fuss and trouble on it as I can.

Thanks.
-Matt

RE: O2 sensor problem
 

He may not have a bad o2 sensor there is a ton of ethenol being added to gas tell him to try a can of dry gas or some fuel system cleaner first to see if it fixes the problem. I believe there is one sensor right in the manifold and one under the car just before the cat.

RE: O2 sensor problem
 

I also have the P0420 code... did replacing the o2 sensor take care of the code? I'm hoping it's the sensor and not the converter.

RE: O2 sensor problem
 

What year is your car?

RE: O2 sensor problem
 

How's this for a timely response? lol Sorry, we thought we had it fixed for awhile there. Then I forgot I had posted here.

We have a 2003. Still have the CEL light on. Replaced the sensor that's on the side of the air filter box, something to do with emmission controls - I can't remember exactly what it was called. Noticed that it was cracked where the vacuum line connected. The light stayed off for a couple weeks after this, but then came back on. I haven't been too concerned as the car has been running fine. No loss of power or fuel milage. But, I figure I ought to track it down and get it fixed here soon...

RE: O2 sensor problem
 

try reseting codes by removing ecm fuse for more than 30 seconds (engine off). If code reappears again your gonna have to test circuits and sensors that you're getting codes for. If you have a 4 cyl, the o2 sensor is 1 on exhaust manifold, 2 after cat. You can test the restance on these to see if they fall in range. You will need a factory service manual or othe manual to do that.

RE: O2 sensor problem
 

id would say that you need a cat my good man

1135 is b1s1 o2 sensor heater malf. that sensor is bad. no way around but to replace it.
usually if all of these codes are present it means your cat is totally nuked. the theory i have heard is that if the cat becomes plugged it will set a p0136 because not enough exhaust gas is reaching the sensor behind it (b1s2) and the sensor is telling your computer the cat isnt working as it should be. the buggered flow will also toast the sensor in front of the car (b1s1)

we have tried to replace just the sensors, and the codes always reapperar somewhere down the road. a cat with both sensors it the only solution we have found.

RE: O2 sensor problem
 

Before you go and replace the O2 sensors, you should test the voltage coming out of the sensors with a volt meter. The Hanyes manual tells you how to do it and what it should read. It should fall between some range when the engine is running cold and when it warms up. Does the exhaust smell funny?

I had the same problem (not the same codes though) and could not get any voltage reading on the air-fuel ratio sensor (only in CA vehicles--otherwise known as O2 sensor) at the exhaust manifold. I bought a new AFR sensor from a local Toyota dealership, some anti-seizing compound from Autozone, and replaced it myself on my 98 Camry LE 4 cyl.

Afterwards, I reset the codes from the OBDII reader and I was good to go. No more funny smell coming out of the tailpipe.

RE: O2 sensor problem
 

What the guy above said. A voltage when warm from .375-.7 and make sure it does'nt stay at a single area for to long and blip the throttle make sure is changes volts somewhat quickly.
As a norm if your car is around the 1990 mark and hasn'nt had a cat change yet and it is a eff. code chances are it could be a bad cat.

Note: If you have had a bad running engine or have overheated a cat that kills them as well.
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RE: O2 sensor problem
 

I have Camry 03, Japan version SE, 2.4L, 4cyl.I had P0420 appear already before and was able to reset it via OBD. Came back yesterday after about 3 months and 5-7k miles later. My mechanic checked it last time after I was able to clear code. His OBD (higher end one which inquires what type of vehicle u r testing) All sensors were probed for feedback and everythig was normal then. I have 99,900miles on it and make long trips very often (Field Service). I noted thatduring the earlier years of thevehicle, the exhaust fumes was too rich, even co-worker noticed it. Butu know how it goes, bring it in to the dealer unless you have sufficient proof, they would declare car is normal since it was stillunder warranty. Anyway,my trusted mechanic has declared it is CAT that needs replacement, and it is logical to replace O2 sensors along with it. I knowit can be called shotgunning but I guess that is just howthe cookie crumbles. Being from CA CAT conv. is more expensive. Ihave been using K&N air filters since 5k miles of car. Dealer blamedK&N as cause of MAF to go bad before. Iasked forold part and cleaned it, popped it back in, works fine.I hate going to dealer, such a rip off...Checked air filter case after the filter, wiped it with white cloth...no oil or dust indication.

Question is will replaceing cat and sensors take care of problem? will it correct for air fuel mixture evidently?

Otheritems to be noted...Use 91 Octane fuel which I have noted just gives morepower for car...Been using it since 20K miles. Performed tune up (plugs replaced with after market Iridium, same as specified) 3 mos ago.Fuel consumption is average of 23-25mpg combined. Noted just recently of a long tripLA to Madera, CA thenback again...30mpg...