jsmith27

My 2000 RX300 got a check engine light which stayed on for 1000 miles, now I get an occasional low rough idle.

I am going to go to Autozone to borrow there OBD II reader; I belive it will read the codes?

How do I clear the code to see if it comes back?

Do Lexus codes clear themselves after so many starts?

I will post the code when I get it.

Thanks for the help.

Lexmex

Welcome to the Club.

Yes, their code reader should read the codes.

Generally after 3 starts, they should clear themselves if nothing is wrong at that point in time, though sometimes they can clear themselves on the road (light just goes out).

You can try clearing the codes with the reader, but if the problem is still there, the code is going to come back.

Post the codes and will let you know.

lbcrx300

i have a quick questions, ive used this site before for something similar to this, so maybe it could help me out again.

A few weeks ago my car was idling real low, and then i started having an engine 2 misfire, so i change the coil pack and the spark plug, then I cleaned the iacv and it was running like a charm, now all of a sudden it sounds real funny sometimes when i press the gas...

its running like a charm, no lights on dash nothing, but sometimes when i start it and press the gas it sounds just rough, i dont know how to explain it at all... any suggestions?

ExPatBrit

Code readers are cheap now, I would seriously consider investing in one if I were you.

Harbor freight sells a code -reader (Cen-tech) for $40-50. I bought one about 2 years ago and it has saved me $$$ and a lot of worry. It's a bit basic as it only displays the code but Google will find what it means for you.

That way you can check the code write it down and come back here and ask the correct question.

Frequently parts places recommend replacing parts that are not always necessary, these guys are not usually mechanics.

Lexmex

What rpm are you seeing in idle at Park, and also when in idle when you move it to Drive (when it is rough in both cases)?

jsmith27

The codes I got are:
P1130
P1135
P0171

Thanks for any input, I am out of town now and dont want to take it to the stealership, not sure what to do?

Nad1370

More than likely you need a new A/F sensor B1S1.
Get a Denso brand and nothing else.
This location is in the rear bank exhaust manifold firewall side.
Access through underneath the car.
Very easy to replace with the right tools.

jsmith27

Thanks for the picture.

Is the sensor before or after the flexible exhaust piece that typically goes bad, because mine is leaking and maybe this could cause the A/F codes?

bearbrew

The sensor is in the exhaust manifold forward of the flex duct.

If you do change the sensor the lowest price for the Denso A/F sensor is Amazon.com and the P/N is 234-9009.

There are several threads here on the forum on replacing the sensor.

When I replaced mine the hardest part was getting the connector apart due to limited space. The replacement took about 20 minutes after I got the right front jacked high enough for access. Don't forget the jack stand. I used an open end wrench and a dead blow hammer to break the sensor loose.

jsmith27

Are there only two oxygen sensors on a RX300? (front and back exhaust manifold)

Are they both a 234-9009?

I am planning on buying it online and taking it to a shop to replace.

bearbrew

There are only two A/F sensors, one is located as pictured above and the other is aft of the radiator in the front exhaust manifold toward the drivers side. You can see the forward one when you open the hood and look between the radiator and engine. Both sensor are the same P/N, 234-9009, and not that difficult to replace.
Replacement write-ups are here on this forum.

Bear