!check Engine Light!

[brandondiem]

Well the check engine light turned on on my RX300 today- 55k miles and regular service. I stopped at a Toyota dealer on the way into work and after waiting 1 hr they said they do not have the right adapter to hook it up to the diagnostic machine. The car is not performing poorly but I have noticed a bit of lag in the high end while traveling on the highway. I also noticed that the car shutters a bit after ideling for 1 minute. I have had a K& N air filter with a Tornado Air installed for over 1 year now with no problems. Could this be part of the reason? Anyways I had Lexus pick the car up 1 hour ago and I am keeping my wallet nearby. Has anyone else had this problem? Any suggestions or advice would be appreciated.

MAF Sensor? O2 sensors? Others?

[strmrdr23]

depending on what code they tell you it is, it might be just a dirty MAF sensor...i had the same issue just recently...about the same mileage but i had the trd airfilter instead (i am told that k&n makes the trd one, tho)...anyways, the error code was like P0171 or something like that...bank one sensors? i don't remember...if that's the error code, it might be the O2 sensor or MAF. clean the MAF first before buying an O2 sensor...see if that fixes it. if not, good luck, man...hope that helps

[BadBrad]

It could be a multitude of problems - without a scanner you'll never know. But go for the easy stuff first. Is your gas cap on tight and not leaking vacuum? The cap should click at least twice - otherwise its not on correctly. The computer usually knows when there is a leak at the cap.

The next most likely culprit is gonna be an oxygen sensor - these are easy to fix, inexpensive to buy, but cost you the same for diagnosis at a shop as simply buying your own code scanner.

Some of the corporate auto parts places will scan the computer for you. Autozone does this.

[rrf]

I had P0171 which is "System Too Lean (Fuel Trim)".... and thx to this forum and others I decided to clean the MAF with throttle body cleaner, instant success. I used Gumout Throttle body cleaner and then used compressed air on "low". This is a 1/2 hour job.

Symptoms were: Early model RX300 (one of the first)

poor shifting, hesitation, loss of top end under uphill "freeway" loads.

Good luck everyone.

[rrf]

Forgot to say,

yes the intermittent P0171 will show as a CEL (Check Engine Light).

The P0171 and CEL will register but only intermittently with a dirty MAF.

I used a scantool to reset, and P0171 and CEL stays OFF for a few days, but eventually it will return.

But the driveability symptoms I mentioned above will persist with or without CEL until the MAF is properly cleaned [or replaced as Lexus would have your do]. about $150 in parts, + labor ???

DIY for $8 Gumout Throttle Body Cleaner and 1/2 hour, EASY.

ALSO, more good news....I believe a battery disconnect will clear the CEL. I do recall resetting CEL with battery disconnect once :)

[sgriffith]

Yes, disconnecting the battery will clear the CEL....I have done it once. I did leave the battery disconnected for about 15 minutes to make sure it was reset. Not sure if it was necessary, but figured it couldn't hurt. The only bad thing was I had to reset the memory seats, radio stations, and all that other stuff that makes a Lexus wonderful!!

[2000RX3]

i have a 2000 rx 300 with 60,000 miles on it, the check engine light came on, went to a lexus dealership and they said i needed a new MAF, they call it something fancy though. Thay said it wound cost around 500. $ to fix, I talked to the mechanic and he told me to spray carberator cleaner on the MAF, said it happens alll the time, no need to replace the MAF. problem fixed.

[SKperformance]

True ,cleaning a maf with throttle body cleaner works but use it properly .

Go back and kick the person in toyota in the !Removed! for saying they didn;t have the right adapter.

they have the damn thing it is OBD 2 same plug and codes for lexus and toyota as well as every other car in america since 97, they are full of !Removed!, probably too busy so they brushed you off with a stupid answer.

[customrx]

GOOD CALL SKEP....... ;)

[customrx]

SKP*

[99_rx300]

can someone tell me exactly where the mass air flow sensor is ( somewhere behind the air filter box?) and give a description of it?

Thanks

99 rx300 w/ 120K- symptoms are sluggish acceleration at top speeds

[eric618]

I thoroughly cleaned my MAF with contact cleaner and light compressed air after a P1071 code came up. It's been well over 2k miles and no problems since. Props to JPI for helping me out with the problem.