tman1352

I have this same problem and have found reviewing this info. very useful. I do not have a driveability or gas mileage issue so I will check out the hoses and O2 sensor when I do my oil change service in a few weeks. Thanks all.

sweeks

I disconnected and reconnected the small vacuum hoses at the front of air filter box and I took of the gas tank cover and put it on again.

Lights are gone. Can't help but wonder if a sensor is going.

Other than that, my RX works great.

autoexper2

There are so many reasons for check engine light...
Check Reasons behind Check Engine Light Flashing..

Yimer

Last week I had coolant replaced/flushed. Oil changed (synthetic), and the fuel line system cleaned. Air filter and Cabin Air Filter changed. After I drove off the garage that did the job, CEL and VSC lights came on. I took the truck right back. The guy said the scanner read lean air and added it was probablly because he did not replace the Air Filter properly. The lights were reset. 2 days later they came back on. I went back to the shop. They said it is reading code P2237 ( Sensor 1 Bank 1) and has nothing to do with the job they did. They said only the part costs $379.00. I don't see P2237 in the Poll Results for CELs Codes. I need advice. Shouldn't the shop bear the responsibilty for causing the light?
RX300 2003
134,000 Mi

kalali

Not if it's totally unrelated to the work or near the area of their work. Sensors can fail with no prior warning. Regardless, $379 for parts alone seems too high.

tman1352

I bought my Rx300 from a Lexus dealer and two days later the same lights came on. They obviously knew of the problem and simply cleared the codes and hoped that they would not reappear long enough to sell it. I have cleared the codes twice and checked the hoses at the air cleaner. The o2 sensor looks new. I have no driveability issues and get 20.3 mpg, which I fig. is ok so I ignore the lights. If anyone has any other ideas I would love to hear. I bought the car from Lexus of West Palm Beach.

salimshah

What codes are you getting?

Please visit the place who sold you the vehicle and tell them that your cel light is on and ask them to print out the history of the vehicle. They may try to say it is not their problem as the vehicle was sold as is. No harm is visiting. I do suggest that you remain polite but insistent and talk to sales manager or dealership manager.

Salim

sweeks

Recently the CEL and VSC lights came on...did the scan and got a P0037 code.

Ordered the b1s2 oxygen sensor off toyotapartscheap.com oem part # 89465-48180.

Replaced the sensor, cleared the CEL and VSC lights ... noticed better fuel consumption

tman1352

Just changed my upstream o2 sensor last week. The 3 warning lights on the dash that is 1 check engine 2 VSC and 3 TRAC, have gone out, there is no noticeable change in mpg or performance. One shop had tried to charge me for 1 hour diagnostic time and that we could "take it from there" , they also told me that if it was the sensor they had it for $285. plus tax. I left there in a hurry. I got the part from Ebay for $90. and had it installed at a chain parts store/garage for $123. I wish the dealer had dealt with this before I bought the vehicle even if they had to charge more for it.. I am comfortable with my Lexus and really appreciate all of you fine folk on this forum who are so willing and helpful with advice. Thanks again.

jasonc75

Hi! First post! Although, I've been reading the forum for a while now. Thanks for all the help!!

02 RX300. 140K miles.

I've been trying to diagnose and repair the same or similar problem to no avail. Cel and VSC lights illuminated. Auto zone gave me codes P0171 and P0145; lean on both banks. I didn't notice any performance issues for fifty city miles or so, I only drive about 10 per day, except I could smell gas or exhaust fumes and an occasional rough idle. I have also since noticed I don't hear a vacuume or suction sound when removing the gas cap for fueling.

With each repair attempt, I've reset the computer by pulling the fuse for a few minutes and replacing.

Here is a list of what I've already tried to resolve the problem:

1. Cleaned MAF sensor with MAF cleaner, visually searched for loose vacuume hoses. Ran a bottle of fuel injector cleaner through with full tank of premium gas.
2. Replaced gas cap with new, OE cap from dealer.
3. Replaced MAF sensor with rebuilt sensor from autozone.
4. Cleaned throttle body, flaps and Idle Air Control Valve with throttle body cleaner. Valve was indeed sticking some.
5. Again replaced the MAF sensor with another rebuilt one in case the first was no good.
6. Replaced PCV valve with new, OE part from dealer. It was gunked up but still rattled.
7. Tightened front valve cover bolts. I noticed a little oil seepage from cover. Bolts were really loose.
8. Used propane to search for a vacuume leak. I didn't hear any change in engine sound. I probably could have done this more thoroughly, but I'm afraid I'll start a fire in the engine:/


I've been driving the car in between each repair and it runs really well at times and then all the sudden I'll smell the lean condition again, feel it start to run rough and shortly after... Cel and VSC lights again. For the first time, the other day, the car wouldn't start without depressing the gas pedal. Since then, it's been idling very rough at times and then others, no problem!!??

I've been pouring over these forums for anwers and gather that it shouldn't be the O2 sensors because I'm running lean on both sides.

I have no idea where to go from here. I'm certainly no mechanic but I work as a handyman and have tools. I'd love to be able to resolve this issue myself. Any feedback would be greatly appreciated!

Thanks for any help in advance.

Jasonc75

carguy07

Check those codes again P0145 does not make any sense to me??

jasonc75

Oops. P0171 and P0174. Thanks for the reply. I just finished test driving it and I've FINALLY resolved the problem. ECT sensor! I swapped it out with a new one from autozone. $23.00 and a Lifetime warranty. She purrs like new, espcially with all the other stuff i did trying to find the problem. The procedure couldn't have been more simple. Hallelujah

jasonc75

Noooo! Not again! It was running perfectly after the ECT swap. I didn't even reset the CEL just to make sure it wasn't running better due to the reset. Now, three days later, it's back idling really ruff again and smells rich. Reset the cel, 6 miles later, lights back on. P0171, P0174. I'm gonna try another ECT sensor. Could there be a short somewhere thats burning out the sensor? Im also gonn check the fuse box. I replaced the battery just a couple days before the pro lem started and i accidentally grounded out my wrench while tightening the positive connection; sparks flew. Maybe I blew a fuse somewhere? Im thoroughly confused. Any help would be greatly appreciated.

tman1352

Jasonc75, sorry to see you having these problems. I suggest you change your upstream o2 sensor. It is capable of turning on the lights you describe and giving a host of different codes. Some shops will go to town on you doing all sorts of diagnostics, but this seems to be a common problem and fix. The upstream o2 sensor is located in the exhaust manifold in the front of the engine. It takes about 15 minutes to change. I bought a Denso unit which is OEM on Ebay for $90. You can also get it from a variety of other places. Please let the forum know how it works out.

tag8818

Great messaging on this forum. I appreciate the input.