hi guys. need help here. the check engine light came on and i got the above error codes - system too lean. i searched the forum for possible solutions and i did the MAF sensor cleaning. I twice sprayed electrical cleaner on the 2 tiny wires inside to make sure its clean.

i reset the the CEL and after about 20 miles it came back on again.

does this have something to do with a dirty air filter? i just checked the air filter earlier and its dirty.

i have a 2004 rx330.

please help. thanks in advance.

regards,

EC

 

i found this in the internet:

If you have a phillips screwdriver and follow my directions exactly I can save you about $480.
Remove the two screws that hold the MAF on the intake near the air filter, go to an auto parts store or electronic supply place and get a can of spray electronic cleaner, spray the inside of the air flow sensor, you need to get it into the small opening where the platinum sensor wires are, they get coated with dust and other gunk and confuse the computer because it gets the wrong signals,clean the wires until the look shiny, reinstall it, you may be able to clear the check engine light by disconnecting the battery and waiting 10 seconds, also replace the air filter and you should be good to go.

i think i did the way it was instructed above. should i do a more thorough cleaning? spray more than twice. it will be difficult to clean it with a q-tip as the wires are very tiny and fragile.

 

did you check your gas cap?

 

yep the gas cap is tight. now that youve mentioned ill go tighten it again. i just want to get rid of this problem. its not worth it for a 20k+ car.

 

Both are lean errors, with the P0171 being among the most common of all CELS, here is my list:

injector blockage
dirty air filter (that is a big one)
dirty PVC filter
IACV blockage
gas cap
Exhaust pipe leak (right around the manifolds off the engine block, usally a hairline crack can be seen

and finally though probably lesser so, A/F sensors (this can be checked by a mechanic with an advanced scanner...need not be Lexus/Toyota, but they can read both banks 1 and 2)

 

Well, here is what I would do first:

Put in a new air cleaner. A dirty one should make it too rich, which is opposite what you have, but what the heck? If it is dirty, you need a new one anyway. Maybe the computer will be happier.

I would fill up wtih the highest octane gas I can find so I do not get any detonation damage driving it. Then I would pour in a big bottle of Techron to clean the system.

Drive around and reset the error codes after 100 miles and see if they stick.... and good luck!

 

This is covered under warranty, unless you have hit the mileage clause. There was a TSb on this...running lean....Good Luck!

 

thanks for the responses. i go over it on the weekend and see what happens.

 

What does the dealer say? Most Lexud dealerships go over and beyond to help fix you up? I mean its an 04....go ask

 

heres the latest. i took it to the dealer and they kept the vehicle for 1 week. they replaced the IAC Valve - idle air control valve. so far its working good. i also noticed less shake in the engine and better transmission shifting. i think slightly improved mpg also per avg mpg display. the dealer did not charge me for anything.

here are the comments on the receipt:

concern: customer states check engine light stays on
cause: faulty iac valve - idle air control valve
correction: replace idle air control valve, clear diagnostic codes and retest

hope this will be good information for anyone who would experience this kind of issue.

 

Emission related warranty is 90 months...or 80,000 miles...if I am not mistaken, this falls under this, I think.

 

really? how do i find out if i still warranty on this lexus? they never mentioned anything at the dealership. is every lexus qualified to a standard warranty?

 

There is a federal emissions warranty, 8 years or 80,000 miles, whichever comes first.

 

thanks. thats info i needed to know

 

hey how do i know if my RX has 2WD or AWD?