WarRX

My '02 RX300 recently began experiencing a noise from underneath the vehicle while accelerating. Yesterday the noise became very,very loud. I looked underneath the vehicle to discover the situation indicated by the arrow in the image attached. The Check Engine and VSC lights also came on shortly after the very loud noise started.

Does anyone have an idea of what *may* have happened here? I have checked the RX300 Exhaust Diagrams (from the online parts dealers) and I am not even sure what this disconnect is, possibly a sensor? Is the remedy as simple as attaching to the location again and securing with new nuts (M10 - 1.25?)? I have checked the bolts in the image and the threads are fine so I am at a loss for explaining the current situation.

Thanks in Advance for any suggestions.

salimshah

Yes, just put the senor back in and put in new nuts. The CEL is due to the sensor.

I would suggest that go to the dealer and ask if there are any gasket and lock washers that need to be added.

I would highly recommend that you buy the stuff from dealer. If it is too inconvenient then very least buy stainless-steel stuff. Any thing else will give you lots of trouble later.

Did some one work on the sensor? All nuts and bolts have to tightened to a specified torque (I am **** about specs) and what happened to you would not have happened if the nuts were torqued properly.

If I find my manual, I will post update.

For now take a wire or string and tie up the sensor to the body to prevent a possible break in the wire.

Ok here is the update:

Two items go between the senor and the hole in the exhaust.

nut \
sensor -+-> Heated Oxygen sensor Protector -> gasket --> exhaust hole.
nut /

The protector plate may not be a stocked item ... so give the dealer parts a call to pre-order. As I said I am **** about this and would get the protector. You ask the parts ppl to ask a Lexus tech if you can do without it.





Salim

WarRX

Salim thank you for your description and advice. I am going to temporarily secure the wire until I can get to an open dealership (b/c of the holiday weekend).

In June '09 I had the Air Fuel Ratio Sensor replaced at a Lexus Dealership when the Check Engine Light/VSC appeared and computer was reporting a P1135 error.

No one should have been playing with any of the sensors since then - which for me makes this event highly suspicious.

I just can't imagine 2 nuts twisting themselves completly off of those long bolts. I don't want to imagine it was the hijinks of a recent mechanic used but I am at a loss to explain.

Looking to the great resource that is this forum for any other similar experiences.

salimshah

Lexus of Austin is open Monday.

It is long shot, but you might call the dealership that worked on your RX and ask if they worked on this sensor. If so tell them that it took this long for the nuts to fall off. It is 1/2 hr labor (my estimate) and $30 for parts (my estimate).

Lot of detective work can be done by looking at the threads. Any portion that has junk in the groove has been exposed for a while. Clean threads mean, recently the nut has moved over it.

The wire support is already there. You need to support the senor now, otherwise it would dangle and flex the wires.

Salim