McGuyver

My wife's 99 ES300 has 135K miles, runs like a top, but she has complained about the lights flickering while she is driving - I will check the battery and alternator, but I was wondering if there is something else I should look for if I find nothing wrong there.

She has also said that the car squeals a bit braking and makes the steering wheel "jerk back and forth" - I drove the car and with light braking, there is an initial short squeal, but quiets with more pressure, under hard braking there is heavy shutter Okay, I know that this probably has to do with either the pads, calipers, or more likely the rotors ( warped). My question is - If it is the rotors, do I really need to replace front and rear since the biggest part of the load is on the front, and should I go for the metallic pads to reduce dust?

OK.

The o2 sensor won't cause engine damage. They can't affect fuel changes enough to do much more than give you crappy gas mileage & raise emessions.

It could have just been a rare defaulty sensor, or it could have been killed with some kind of engine treatment.

In general, if your gas mileage doesn't suck & you can pass emessions, there's nothing wrong with o2 sensors. Change them every 100-120,000 m as preventative maint along with the cat convertor<s>.

The only way to test oxygen sensors to time how long it takes them to reach operating temp at a constant 2,500rpm, or throuh normal crank & drive (Idling to let an engine warm up is horrible), and watch their output & watch how fast they respond.

You can't test them by resistance, it's just grab a voltage meter & watch their output :\

You can, however, unplug the o2 sensor & connect up to one of the diagnostic ports (if you know the pins) & test the resistance across the oxygen sensor heater circuit.

The rest of that just really *BLEEP*es me off.

Quit going wherever you're going to get your work done... They're ripping your sclong off & beating you with it. $675 to change an oxygen sensor my !Removed!. They better have thrown in some seriously disturbed sexual favors for $675... You wiggle your arm down the firewall, unplug the wire & take it off with a deep well socket, or a wrench.

You're talking something that takes a half an hour at most, and that's just giving the exhaust 20 min to cool down!!! It takes 5-10 min to do if you put a glove on & just do it. Maybe 10-15 if you splice a new one in.

Generic Bosch splice in oxygen sensors for your engine run around $70usd. The same Bosch sensor with the correct pigtail on it (plug & play instead of splice in) runs about $90-110usd.

The actual Denso o2 sensor runs anywhere between $150-$230usd.

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I stopped that after the first sensor went out ( firewall side ) I replaced the front (radiator side) about a year ago along with the one after the cat. The dealership didn't even give me the jar of vaseline to ease my pain when I purchased those.

Don't have to worry about them working on this car.

Thanks for the advice.

I am pretty good at the old school stuff, but I just haven't worked with the heavy electrically monitored systems much.

Thanks again.

Thanks for the information.

I will check for cracks or leaks at the rear manifold this weekend.

I replaced the firewall sensor last night with a Denso unit I purchased for less than $200 online (AAA-Import Parts). The unit was marked as an oxygen sensor, but the seller confirmed that this replacement unit will work without a problem. I hope so.

I still have the old sensor on my work bench and I would like to verify that in fact the sensor is bad. Of course, if the CEL/TracOff light goes out, then that would be confirmation enough.

I am still curious though how a sensor could fail in less than 30K miles. SHould I be checking something else?

And...

I am concerned that this sensor may have been bad for longer than I have been led to believe. How long can you continue to operate the car on the default settings without causing other problems? What can I expect to happen...or am I just being paranoid?

Thanks for the info.

The codes indicated that the Bank 1 Sensor 1 was malfunctioning [P1133 & P1135] and I was told by the dealership that this is the unit at the firewall. True?

[For some reason, I cannot trust a dealership service manager - maybe it's because the my new '84 Volvo GL caught fire and burned to the ground in a dealership parking lot with its first oil change. BTW: I did get a brand new car, baby seat, a complete set of Craftsman tools which I had just bought that morning, and an apology. I never went back there - but that was the same Volvo my Son crashed].

My wife's ES was made in Oct 98, so that puts in the midst of the sensor problems of that time. Evidently, the complaints got bad enough that Lexus issued a TSB (#EG004-99). The bulletin only states if routine checks do not solve the ECU code to replace the original AFI [#89467- 41020] with the supplied replacement [# 89467- 41021]. It would seem that there IS an issue with the Bank 1 sensor on this particular model, if a TSB was issued for the cars made from 8/1998 to 7/1999 ( Cal - 8/1997).

FWIW I believe there is something amiss with the ECU & AFI interface.

At this point it doesn't matter, my wife loves her car and I have to keep it going for her, so I will snatch that bad sensor out every three years if need be.

There are a few online parts suppliers that offer a Denso replacement unit [C5015-137284] for around $200, but I have never dealt with any of them.

Can anyone tell me if they have dealt with Auto Parts Place (.com), The Parts Bin (.com), Buy Auto Parts (.com) or Parts Discount Warehouse (.com)?

Where did you get you replacment parts?For the prices mentioned it would sounds like what the dealer charges.

I would search

as your MAF could use cleaning

as well as this is a constant question for a rear failing o2 sensor

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I got the sensors from the dealership, because at the time I could not find a supplier for the 4-wire sensor. I cleaned the MAF when I changed the front bank sensor.

The car has a history of CEL events. Every so often the CEL would lite off and then in a day or so or even sometimes just a few hours would self extinquish. This has happened so often that my wife has started to ignore the indicator all together. It wasn't until I drove the car while she was on a business trip that I noticed the CEL and had the codes checked. I asked her how long it had been on and she just said "a few days...maybe longer". It is really no telling how long the car has operated in the default mode.

I am a newbie, but I have to know if anyone else has had problems with the front and rear bank AFI ( air fuel indicators) or what was once known as oxygen sensors.

I purchased my '99 ES300 (used - 55K miles) 3 years ago from a Toyota Dealer and within two months, the CEL and Trac Off lights came on. [ BTW: The Trac Off light will come on anytime the CEL is on] When the codes were checked, it was the rear bank AFI and $675 (Yeow!) later that sensor was replaced.

Almost 60 days later the front bank AFI sensor failed and I replaced it myself for $497 (sensor cost + sales tax) Yeow!

Since that time the Peddle position sensor has also failed and been replaced.

Last week the CEL & Trac Off light came on again. The codes indicate the rear AFI sensor has failed again. That sensor failed in less than three years and 36K miles

Is this normal? The Service manager at the Local Lexus dealership says it "happens occasionally".

I find it hard to believe that an oxygen sensor should fail that quickly - it's just a heated wire for crying out loud. My volvo had over 250K miles when my older son crashed it, and the sensor in it was never changed. All 5 of my trucks have never had a bad exhaust sensor.

Has anyone else had this problem? Could there be something else that is causing these sensor to fail?

I need help with this. This is my wife's car and I feel like contacting the regional manager for Lexus and ask him, if I could find out who that fellow is.

Any help will be greatly appreciated.