Flat Spin

I'm new to the forum as my 2003 RX 300 has had 63,000 trouble free miles until yesterday. My wife was driving and called me with the report of the VSC and Check Engine Light being on. The vehicle acts fine and the gauges are reading normal. I checked the fuel cap as the owners manual suggested for the engine light but no results. Any advice is appreciated. Thanks in advance.

Lexmex

Welcome to the Club.

You can do 1 of 2 things (as you indicated it was acting normally).

1. Go to AutoZone and have the code read for free and let me know what the code is so I can tell you what to do.

2. Either pull the negative battery cable off (make sure you have the key out of the ignition) or pull the EFI fuse located in your fusebox in your engine bay (also with the key out of the ignition), see https://www.clublexus.com/forums/sho...8&postcount=15

Number 2 should reset the light assuming there is nothing permanently wrong in your system. Inevitably this error is usually the P0171 lean air code.

Driving on a P0171 is okay if you don't feel anything else acting up.

bob2200

It would be interesting to conduct a poll of what the cause of the check engine light condition is most commonly. In my case, it was an oxygen sensor failure in 2005 and again recently.

Flat Spin

Thanks! I'll ride over to the A.Z. this morning and get the codes.

Lexmex

That is an excellent idea. In the afternoon, I will go through volume 1 of my service manual and pull out codes and make a multiple choice poll.

Flat Spin

The computer reads three codes:

P0135 (O2 Sensor Bank 1 Sensor 1)
P2237
P2A00

Is this something that a mechanic needs to address or can it be done with my wrenches and sweat?

Lexmex

Did you have the codes reset (or deleted) after reading them?

Reason being is that I would want you to drive and see first if the light comes back on again which then indicates a permanent (as opposed to temporary problem).

As far as the codes, they are all related to the O2 sensor on the back part of the engine (noted in the photo below).

It is possible to buy this sensor yourself and replace it. Kind of a PITA to remove (some others in the forum who have had firsthand experience can offer some hints on this).

Again, you can also follow my advice in the other post to reset the light via the EFI fuse or negative battery cable (just pull either one out or off and then put it back in or reconnect, respecitvely) again without the key in the ignition and that will temporarily reset the code.

Flat Spin

No I did not have the codes deleted. I just tried the negative cable disconnect and had no luck. Both the VSC and Engine lights came back on. Any idea about how much an O2 sensor costs and where should I order one?

Lexmex

Try it once with the EFI fuse. Keep the fuse out for at least 10 seconds and then put it back in.

I have seen a lot of forum members order from here, http://www.automedicsupply.com/catal...?&pkey=1416664

You want the one for the pre-cat rear and the one from Denso.

However, you may want to let other members chime in before ordering as I have seen lower prices out there.

onepointon

i dont remember off the top of my head, but i believe the 03 RX has A/F sensors instead of o2 sensors doesnt it? you can call the parts department at your local dealership and ask.

either way, Lexmex is correct, it is a faulty sensor. you should be able to replace it yourself. all you need is a 22mm wrench. if you start to remove it and the threads get tight, spray some thread lub on the threads and work it back and forth. you dont want the sensor to seize in the manifold. that turns it into completely different job.

Flat Spin

Johnson Lexus says its not an O2 sensor but an air to something ratio sensor. Whats the difference? They wanted $240 for the part.

Lexmex

Sometimes O2 sensor and A/F sensor are often used interchangeably.

However, so as not to sound confusing, the A/F sensors are sensors like the one in the photo above, and that makes sensor it the Lexus dealer came to that conclusion. There are two of them on your vehicle (one in the photo above) and another one clearly visible if you open your hood and look just behind the radiator and on the exhaust manifold, and you will see one.

The O2 sensor is the one after the catalytic converter underneath the vehicle.

$240 seems a bit high for just one sensor.

bloo1987

Yeah my CEL and VSC light been popping up too. They have been a problem of mine for awhile now. They keeping going off and coming back on every so often. Im taking it to the dealership to see what the problem is. Any ideas?

onepointon

$240 for the part at a dealer is about right. the dealer i work at charges $243.75 for them. as lexmex said, its an air/fuel ratio sensor. it reads faster and more acurately than a normal o2 sensor. they are not interchangable as well.

you could just buy the part from them (recommended), and install it yourself. how much labor are they charging you to install it?

Lexmex

When are they popping on and off?