99 Ls400 Oxygen Sensor Questions

[widowmaker03]

My check engine light just came on. I took it to Autozone and they checked the computer. Turns out the code read I have a faulty O2 sensor. How many O2 sensors are in the car and where is the cheapest place to get OEM replacements?

Thanks,

Derek

[lex90]

4 sensors @ oxygensensors.com

[SRK]

The code should have specified the particular O2 sensor that has failed. You only need to replace that one, and I would use a Toyota/Lexus O2 only.

[RCRFAN3]

I have a 98 LS and I had to replace the left side first O2 sensor. I's under the seat your have to pull up the carpet and remove the gas pedal (just pull hard toward the seat it will pop off) the you will see the wire for it . Not a big job total of about 1 hour. I bought a Denso replacement for $65.00 no big deal I think the dealer wanted around $280.00

[SKperformance]

try to sea foam the engine first to bring it back.

[widowmaker03]

SKperformance,

I'll give the sea foam a try. I'm also going to check the vacuum hoses to make sure none have come loose.

BTW, my check engine code was P0135 = O2 Sensor Heater; Circuit Malfunction (Bank 1 Sensor 1)

[widowmaker03]

Part-wise, are there any differences between the front and rear O2 sensors?

[Elsupremo]

I have the same problem with my 2000 LS ED I Have a couple of questions...

What is a sea foam? Is there a way to get the code readout for this problem so that I can be more

specific to my service rep?

When the engine light went on I though this was a very serius problem the service manager told me to wait it out.

What are the consequences and eventual effects that the car will experience?

Thank you

[Elsupremo]

Anybody got any suggestions??

Anybody There?

[SRK]

Why would you want to bring information to the service manager? That's his job - to diagnose the engine problem, not yours. If your service manager can't access the codes properly, then change service managers.

As to seafoam, forget it. The code is all important and probably you should head to a Lexus, or at least a Toyota dealer to get the car fixed.

Just what prolonged driving with the check engine light on will do is dependant on the code. Running rich can burn out a cat or two. A loose fuel cap will do nothing.

I don't drive busted cars myself.

[Elsupremo]

We are lucky to have a Lexus dealership in our city and a very good service manager as far as I can tell however I always like to get any information regarding a problem so that I can cross reference the information that I get back from the dealer. It keeps them honest and I get to learn a little bit about what CO2 sensors and other new stuff if put in cars now days. Of course it"s about money too (If I could afford a 2006-07 I would not be in this forum.) I am curious by nature so the codes are of interest to me. The sea foam I take is some sort of high pressure wash I assume, I just don't see what it has to do with the sea? When I get to the service department I'll be better informed thanks to the great members in this forum.

[92Lex]

Sea-foam is a solvent that is used to clean internal carbon deposits in engines. Sea-foam is the products name, it has nothing to do with the sea.

[qha_vn]

When the engine light went on I though this was a very serius problem the service manager told me to wait it out.

What are the consequences and eventual effects that the car will experience?

Thank you

not always that bad, what i read in dealer service manual is that, engine light goes on when CPU detects error(s) but CPU is desinged for fail-safe meaning to say if CPU detects a broken down sensor, it will be able to use its own data stored in CPU memory as a backup. the backup data is not ideal for the engine but it gives the car a chance to run so the driver can finish the journey before going to a repair workshop

hope this helps

[SKperformance]

It seems the 98 and up LS400 have an issue with bank one running rich. I have the same problem as of right now. It comes and goes and shows up more often when it is colder as. it is more specific to me sitting at idle in traffic on the highway going no where in drive.

On 3 occasions i will get no code but the engine will start to rev up and down. by itself.

I ran pure seafoam to clean it up and made an improvement but nothing much.

Not sure if it is a dieing injector or coil or maybe a bad head gasket leaking.

[acflye]

It seems the 98 and up LS400 have an issue with bank one running rich. I have the same problem as of right now. It comes and goes and shows up more often when it is colder as. it is more specific to me sitting at idle in traffic on the highway going no where in drive.

On 3 occasions i will get no code but the engine will start to rev up and down. by itself.

I ran pure seafoam to clean it up and made an improvement but nothing much.

Not sure if it is a dieing injector or coil or maybe a bad head gasket leaking.

You add the seafoam to your gas......or oil.......

[SKperformance]

You can add it to either of them ,check the general maintenance section for sea foam threads and instructions.

My bank 1 rich is now gone , and my maf is very clean.

[widowmaker03]

Hi Guys,

I just looked at my power steering resovior and discovered I was almost out. I was wondering if a power steering leak could cause a PO135 check engine error?

[SKperformance]

No fluid leak will cause a ecu code.

[sha4000]

I have a 98 LS and I had to replace the left side first O2 sensor. I's under the seat your have to pull up the carpet and remove the gas pedal (just pull hard toward the seat it will pop off) the you will see the wire for it . Not a big job total of about 1 hour. I bought a Denso replacement for $65.00 no big deal I think the dealer wanted around $280.00

Sorry to bring back such an old post but I didn't want to start a new thread. I haven't posted on here in a while but I always lurk. Just to clarify, when this poster says "just pull hard toward the seat it will pop off" I'm assuming he is referring to the gas pedal. I'm in the process of removing my carpet from the car but can't seem to get it from around the gas pedal. I would hate to yank on this all important part and break something.

[sha4000]

Well I figured it out with some help from other posters in a thread I made in another forum for anyone that's looking for this same info.

http://www.clublexus...ing-carpet.html

[flashedwards]

_{A couple of weeks ago the engine light came on. (1998 LS400) A friend of mine has a large body shop in San Francisco and he had one of his guys check to see what codes it was throwing. He found two.....Now if I can read his writing, this is what he found: 1) Code # P0135---Heated O2 sensor bank 1 sensor 1 heater cicuit malfunction. 2) Code # B2796---No communication in immobilizer system. OK...just where is bank 1 and sensor 1 ? If I can get to it, does anybody have an idea what a replacement unit will cost? I spent a great deal of my younger life working on cars but back in the '50's and '60's most repaires could be accomplished with a couple of sockets, a feeler gauge and a 1/2" and 9/16" wrench. My point is...what in the wide world of sports is an "immobilizer system"? Did the vehicle come equipt with a stun gun? Any and all respnses will be greatly appreciated.}

_{Thanks in advance,}

_{Flash Edwards}

[Micah.Berry]

Bank 1 Sensor 1 is the O2 sensor ahead (towards the motor) of the catalytic converter. Underneath the car, you'll see two exhaust pipes. As the pipes come down from the engine, you should see a corded item (the O2 sensor) which screws tightly into the exhaust pipe. Then you'll see the catalytic converter, and then another O2 sensor, after the catalytic converter. The O2 sensors are "plug and play" meaning there is a clip that attaches to a wiring harness. For your 1998, the clip is underneath the carpet, by the gas pedal. You'll need to pull the carpeting up there, which means you'll need to remove the gas pedal. You'll see the clip. Unplug the clip from its receiving clip in the wiring harness. You can then unscrew the actual O2 sensor from the exhaust pipe underneath the car. It may be on there a little tight. You'll need an O2 socket wrench adapter, which is inexpensive, and fits on the end of your wrench. This tool allows room for the electrical wire. You can pick this up at Autozone, Napa, or where ever your favorite parts store is. As far as the sensor goes, use a Toyota / Denso sensor, which will have the correct electrical clip and voltage. No wire splicing required, and it's not that much more expensive.

The immobilizer system is a security system for your car. It essentially disables the engine (immobilizes) so that it cannot be started, hot-wired, etc. It is the reason that the key fob is kind of expensive for replacement. As far as I know, replacement keys come from Lexus. You can get the exterior key fob, but the electrical gadget, with the buttons that open and lock the doors, only comes from Lexus. I bought mine from Sewell Lexus in Dallas.

Hope that helps.

Micah

[Sanpete]

If I understand the comments from 1998 and 1999 LS400 owners in this thread, you have to get at the wiring connector for the bank 1 sensor 1 (pre-cat) O2 sensor from under the carpet on the driver's side. RCRFAN3 makes it sound like the sensor can be accessed from there too, but Micah says you get to that from under the car.

Anyone care to clarity or correct that? Can both the connector and sensor be accessed from one place, or must one do surgery from two sides?

[Micah.Berry]

If I understand the comments from 1998 and 1999 LS400 owners in this thread, you have to get at the wiring connector for the bank 1 sensor 1 (pre-cat) O2 sensor from under the carpet on the driver's side. RCRFAN3 makes it sound like the sensor can be accessed from there too, but Micah says you get to that from under the car.

Anyone care to clarity or correct that? Can both the connector and sensor be accessed from one place, or must one do surgery from two sides?

The pre-cat O2 sensor wire is first accessed from underneath the carpet. Then get underneath your car and look up where the exhaust headers are. You'll see the pre-cat O2 sensor with a wire leading out (that you will have accessed through the carpet). You'll then get your socket wrench with the O2 sensor attachment to unscrew it. It will take some force, especially if anit-sieze wasn't used. There is also a post-cat O2 sensor, that you can easily see underneath the car. The "cat" is the catalytic converter.

[Sanpete]

Thanks Micah. Makes me wonder if it wouldn't be easier to use a universal sensor and just cut the wires from underneath instead of messing with the connector from inside. How much room is there for that? Or is it easy to get the gas pedal off and on and get at the connector?