So I took my car to my nearest lexus dealership, where they informed me a number of things wrong with the car (maintance, my check engine light was on, etc).
Long story short, I ended up spending close to $2300 for everything. Took the car back the very same day b/c there was this loud noise coming from the car and the check engine light was back on. Mechanic from lexus drives it, and tells me it could be the grade of fuel I put in, or the fact that the car is low on gas. Right... they call me back to tell me they have replaced my manifol free of charge. What they didnt tell me (and it said on the receipt) was that it was damaged during the replacement of the 02 sensor. The check engine is on b/c the mass airflow sensor needs to be replaced. Do that.. another $340! Two days later, the check engine light comes back on, and now they are telling me its the knock sensor, which will cost me another $500 (but they will take off $100, b/c they are so nice!).

Ok.. so does this sound plausible? Could 3 sensors really go bad one after the other??? Also, from my research, it seems all these 3 sensors are somehow related. Is this the case??? Any info/input would be SOOOOOOOOO helpful!

 

minor correction, RX300 does not have a service light, but it does have Check Engine Light. Service light comes on at certain milage while CEL comes on based on abnormality in engine performance.

When it comes to engine performance many things interact with each other and the electronics keeps on adjusting things till one sensor after another gives out of expected range information and more codes accumulate.

I think Lexus was nice in throwing in the free manifold. Although you can say it was damage done by their mechanic, but people who do the DIY know it a distinct possibility and we take the risk.

You did not mention how many miles you have. I had cel due to knock sensor and I played with fuel and cleaner a while, but at 150k it seems it was time for those to be replaced [They can go bad anytime and more likely at 100k+].

Cant comment on other codes.

Salim

 

My car has 77k miles (they did the 75k mile service maintance)

 

How about getting the codes read on your own? Take a trip to Autozone.

Salim

 

99 rx300 and all three sensors have gone at same time - supposedly:
Knock
O2 and
A/F sensor bank 1...

In my case, the car was showing knock code and a p0170 code twice. Definitely needed knock,..but whether the a/f or O2 sensor was needed was unknown. They did the o2 first. That didnt correct the check engine...so then did the A/F......so i'll never know. But my opinion is that the o2 wasnt needed just the a/f


so it can happen..atleast two at once....
The why? Gotta be a computer related thing - either way it's a expensive mystery.

 

Kind of new to this forum, What is the difference between O2 and a/f sensor? I thought they are the same things. Thanks a lot!

 

Czujnik A/F sensor jest trochę inaczej zbudowany jeśli chodzi o element aktywny. Poprostu reaguje szybciej jak o2 sensor,dlatego wykorzystywany jest jako czujnik mieszanki

 

It's Polish.

The A/F sensor does have a different element from that of the O2 for sure.

 

Go with the knock code first. The other sensors can be affected by that, but I would want to see the actual code numbers.

 

A/F sensor (there are 2 in the RX300) are upstream closer to the engine and just on the exhaust manifold coming out of the engine block and are of what helps the measurement of the air/fuel ratio. The O2 sensor (only 1) is underneath the vehicle and after the main catalytic converter. That measures the wavelength coming out of the cat and is strictly an emission control device. BTW, I plan to replace my O2 sensor (just ordered it) and will put up some pictures when I do the changeout. I did my a/f sensors a bit ago. Mexico took a big toll on all of these sensors.

 

Thanks man. Clear enough.