Last labor day weekend, while towing a 16' boat to Fresno from Sacramento, CA, the engine check light came on. I still get 19MHP consistently with full load, three passengers, and towing the boat with camping gears on it.

Went home, checked out the code, it said P0171, system too lean (sp), I reset the ECU, for two days, the light hasn't come back on.

What could be the problem? any help is highly appreciated. Is it related to the MAF sensor? I hear that thing is very expensive.

I have 77K miles on the truck.

Thanks,

Nam

 

it is indeed the MAF. you can clean it yourself and not get a whole new one.

or if you have a warranty/extended warranty, you can get it done free at the stealership.

 

I didn't check, but if P0171 is the MAF, there ae plenty of write-ups in the tech section that you can use to do-it-yourself. If I have time, I (or someone else on the forum) will confirm the the code.

 

Thanks Lee & Rick. I'll do the search.

Nam

 

thats the code i got when it was my MAF.

 

I got system too lean (bank 1) for P0171

 

which is caused by a dirty MAF in that instance... as far as i know

 

Thanks every one for your promptly replies. I've just finished cleaning the MAF sensor. It turns out to be a 10 min. job. I had to temporary relocated the cruise control module to gain better access...but very simple, quick, and easy!

Prior to this, I stopped by Lowes to pick up an "electrical connector cleaner" can, the sensor looks *very* dirty especially from the outer side (facing the airbox). Wish I had the camera handy so I could take some pics. Oh well...it's done.

Hopefully this will solve the supposed-to-be-costly problem.

Nam

 

Yeah I got the same code at 75,000 miles after playing in some dirt one day. Unfortunatley, I had mine cleaned and it still didn't work. Had to replace it

Luckily though, the extended warranty covered it. I remember reading here somewhere that someone's dealer wouldn't cover MAF's under the extended warranty, but mine did
Oh well I won't complain

 

you might be thinking of my thread, where i told them i had the warranty when i brought it in, they still charged me over 300 bucks. then i went back in after finding out it was supposed to be warrantied work.

dont worry, i got it all back.

 

9 times out of 10 it is indeed the MAF causing that code...
If cleaning doesn't do the trick then it will need to be replaced (check junkyards too for parts)

 

Pretacopower:: how much did it cost you for the sensor?

Lee:: lucky you...mine is out of warranty for a long time; however, I hope the cleaning trick will do it.

MTL_4runner:: Thanks for the info. I like your OBD II scan tool. I use the generic one which could only tell me the codes.

Nam

 

Mine was covered under warranty, but I remember my local mechanic said it would cost me $250 installed (or somewhere around there).

 

I got a used one for $150 from a junk yard. Worked great after I screwed the first one up.

 

i just got mine too at a junk yard for $75. It came from a 2002 camry. they sell it at the dealer for $151 brand new. FYI, our MAF is the same as 98-03 sienna, 2002-04 camry, 2001-2 highlander, and the 1st gen RX300.

 

Update!!!

After cleaning the MAF sensor, about two weeks later, the engine check light is back on...it went off for a day and came back on again. Checked out the code, it said P0171 again.

Time for a new sensor I guess!

IS3004Runner: thanks for the infor. if that is the case, I will try to swap mine with my dad's 2000 Sienna and see if it is going to solve the problem.

any other suggestions?

Nam

 

Nope, you definately need a new sensor....
Many have had good luck with getting a used one out of the junkyard too.

 

Did you actually clean both hotwires, or just the obvious bulby thingy? With what cleaner?

 

No wires...I just cleaned the bulby thing with "Electrical Contact Cleaner" and couples of Q-tips.

One even that kind of noticable to me was that I flood the engine with water since the door lach of the air filter was open and I went through water without knowing it...it stalled the engine for a moment and it started right up. The air filter was soaked with water...

I am not sure if that would make the MAF sensor dirty or malfunction...I'll double check and see.

Last result, get a new sensor...thanks to Montreal_4Runner

Nam

 

I will check local junk yard and see what they have. I don't think it's too hard to find.

Thanks,

Nam