MellonC00

How otten do I need to replace these? I know that something like this isn't supposed to break but on my last lexus, I replaced what's called a MASS AIR FLOW sensor. Is this the same thing?

Also how many of these are in the car? Is it just two or more than two? Anyone have any experience with these parts?

joako

I had to have it replaced twice on my last RX300, covered by warranty. But the first replacement had failed within the first week....

MAF / airflow meter I think are the same thing.

Lexmexico

They are the same thing.

Usually, if you use a K&N filter, you are likely to get an error with this sensor. The better thing to do than pay to replace it, is to clean it off with carburator or brake dust cleaner. The red diode usually gets a lot stuff on it and just needs to be cleaned.

melschase

I noticed that you mentioned that when using a K&N filter, the check engine light comes on because of the mass airflow sensor. I have a '99 RX and changed all O2 sensors, but the light still comes on. I still have my K&N installed, do you think that's the problem?
If it is, should I go back to stock or are there other ways to by-pass the system for this to happen? Thanks for your input...

Mel

pdonnell

They really don't start going bad until after 100,000 miles as a general rule of thumb. But anything can break unexpectantly.
.
http://www.aera.org/Techside/oxygen_sensors_101.htm

Lexmexico

If the O2 sensor goes bad, the car automatically goes into an automatic mode to compensate, but it will eat more gas. I have had friends here in Mexico have this problem and they drive to the border when their next service comes up. Others just call up their local Lexus dealer in the states explain the error code and buy the part. They are simple to put in.

When I recently took a long trip into the U.S., my check engine light also came on. I was descending from an altitude of 7,700 feet in Mexico City to sea level, hence more oxygen. but also more garbage from the highway and a lot dust. That set off the sensor. I would then remove the EFI, #13 fuse in your fusebox, with the engine off, and no problem, but everytime I would pull up for gas turn off the car, it would come back on. Had nothing to do with the gas cap, it was the filter.

Usually, the oil on the K&N filter will get on the MAF (happened to me once) and you just clean it. What I do is wash the side facing the MAF and reoil just the front side, this works.

I did switch back to the stock while I was in the U.S. (more oxygen) and no check engine light.

I think the car takes a while to get used to it, at least it did when I first switched to the K&N.

melschase

Lexmexico, Thanks for your insight! Unfortunately cleaning my MAF still causes the light to turn on while the K&N is still installed. I think I'll switch to the stock air-filter and try my luck that way.

Have you had any problems with your struts yet? I'm curious, can Lexus parts be purchased in Mexico for a lower cost? Someone told me that he gets his Mercedes parts there and saves a bundle. Just wondering...

Any other insight in maintaining, improving, and/or fixing our vehicles would be appreicated. It appears that you are more fluent with our vehicles than I am. Again, I appreciate your help!

Mel

Lexmexico

I have to be fluent on my Lexus, there are no Lexus dealers here in Mexico at least not yet. They are supposed to come this spring at certain Toyota dealers. Lexus is a complete novelty, and it gets lots of looks.

You lose very little on MPG by going stock. I lose a lot of MPG by going stock due to high altitude here in Mexico City.

One of my shocks blew when I was rolling up the Nevado de Toluca, a drive-in extinct volcano nearby. I took it back to Lexus of San Antonio and they replaced it under warranty even after hearing my story. Technically, I could have gotten the part here at a Toyota dealer, but it would have been special order. In addition, those rubber supports wore out, but I changed them down here after having my family ship the parts from the states(the way you really get parts here).

To all those going south of the border, here is the way it works. Toyota has only been in existence in Mexico since April 2002. They have the folloing models: Sienna, Camry, Corrolla, Matrix, Yaris (a French-made Echo), 4 Runner, Landcruiser and the Hilux (small-sized pickup truck). Toyota and Lexus parts follow the same system. However, if I given the Toyota part number it almost never comes up in their parts system. However, if I take an Acura (coming in October) or Infiniti (Q45 and J35 sold here) to a Honda or Nissan dealer, respectively, no problem, they can get the part.

On many Mercedes models you can save a bundle on parts by buying them from non-dealer sources in Mexico.

There are so many ways to maintain a Lexus. There are things I find out every day about my RX. All the more reason I loved buying it.

joako

The light needs to be reset before it will turn off.

Erwel

Hi to everybody,

my 99 rx 300 has 70,000 miles in it. I put k&n 9 months ago with 62,000 miles. now my check engine light is on. I have a code reader and it shows the bank 1 fuel/air ration is lean. is this because of the filter? Is any of you guys experience this kind of problem. Any help is highly appreciated

Thanks,

BurnishedGoldRX

What was the code number that you pulled? The early RX300's have Air/Fuel Ratio sensors that like to bite the dust. It might still be covered under emissions warranty(they're $300 each, so anything is worth a shot).

Lexmexico

You probably pulled code number P0171.

This is the most common code error on an RX. I think the MAF is under $150 from my recollection.

However, you need to follow our directions and take a look at the red diode on the MAF. It could be covered with muck and you have to clean it off and reset the fuse. This is the same code I got.

Some of my friends remove ALL the oil of the K&N and still have clean throttle bodies. From my understanding this is almost the same as having the Toyota TRD filter.

Erwel

yes you were right. the code I got was PO171. so I need to clean the maf sensor. do i need to go back to stock air filter? You mentioned your direction to clean it. what is it? Thanks, for your reply, I really appreciate it.

Thanks,
Erwel

LexRX

To clarify, the mass air flow sensor is not the same as the oxygen sensor.

The oxygen sensor(s) is located on the exhaust pipes - they are screwed into the exhaust pipe at specific locations to get a reading on the exhaust gas for emissions.

The mass air flow sensor is locate on the intake after the air filter. It sits down in the flow of air coming in after being filtered from your airbox.

Lexmexico

Brake dust cleaner or carburator cleaner will do. Spray the red diode (the thin wire, you cannot miss it) gently and wipe it gently. Then with the car turned off and the key out of the ignition, pull the #13 EFI Fuse out for about 30 seconds (you may actually need less). This will reset the check engine light.

If you are at sea level, I see no problem in going back to the stock. However, my advice is to wipe off the K&N oil that faces the MAF. That oil serves no purpose except for the front. The Toyota TRD filter is also a good option.