KNou

I have a 1999 4runner and I have codes P0171, P1130, and P0125. Based on research, it appears that these codes could be the result of the MAF sensor gone bad. I cleaned it out about 6 months ago and my truck ran well but now it's starting to lag again plus it failed CA's smog test.

I'm thinking that I might just replace the MAF with a new one to see if it will fix all the codes. My questions follow....

Do you think replacing the MAF will fix the rest of the problems?

Can I buy the MAF from a shop like Autozone, Kragen etc or do you guys recommend buying it from the dealership?

Thanks in advance for your help.

Elton

i got a maf sensor off ebay ya i know but it was a oem unit from a low mile truck for like $30 bucks and its been working fine for a year

Baloo

What part of the sensor did you clean? Many people confuse the part to clean and, in fact, there is a video on youtube that shows the wrong part to clean.

This photo will show you the wires that need to be cleaned. Not on the side of the unit, however toward the base.



The post it came from can be found here;

http://www.toyotanation.com/forum/sh....php?p=2683183

I uses CRC MAF cleaner and do it about once a year. There are ways of cleaning then when they are REALLY dirty you can do a search to find (along with counter opinions) however just doing repeated steps usually does it for me. These sensors are really pretty sturdy beasts.

4runman

First time poster here and I searched on this very topic.

A local dealer wants to replace the Mass Air Flow sensor in my 2000 Toyota 4Runner for $468.98. Is that a good deal?

BajaRunner

Did you read the thread?

I haven't heard of anyone replacing the units. They are cleaned every few years and will continue to work. All you need to do is buy some electrical contact cleaner (found at hardware stores). Unbolt the MAF from your intake (right behind the air box) and spray it out with the cleaner. Let dry, pull EFI fuse for 10 minutes, and the truck should run fine again.

As far as parts and labor is concerned for a new MAF, yes, thats a decent price since I believe new MAF's cost $500+ new from the dealer.

4runman

Thanks for the fast response. In the meantime, I found this tidbit on Carfax about the 2000 4Runner:

"An occasional problem on this vehicle is the failure of the Mass Air Flow (MAF) Sensor. Problems with the MAF Sensor can cause a drivability problem, and may cause the Check Engine Light to illuminate. On some vehicles, the MAF Sensor can be cleaned, and will not need replacement. The cost to replace the MAF Sensor is estimated at $148.90 for parts and $58.50 for labor. All prices are estimates based on $65.00 per flat rate hour and do not include diagnostic time or any applicable sales tax."

Here is the link; info it located further below:

http://www.carfax.com/car_safety/rat...YT4W%204RUNNER

I guess what is important for me is to know where on the engine that the MAS is, so that I can look at it.

diy4runner

Thanks for all the great info on the board. This is my experience with cleaning the MAF. I had the P0171 for a few years. Replaced the front O2 sensor, plugs, wires, throttle position sensor, and finally the MAF. To access the MAF, I removed the cruise control module, and the air cleaner box. A little penetrating oil will help get the MAF screws out.


My MAF looks like:




The upstream side was covered with 10 years of gunk, shown in detail below.




The downstream side is a translucent amber as shown below.




After a good spray with CRC brand MAF cleaner, the upstream side is now a translucent amber as shown below.




I would clean the MAF every few years as a preventative measure. It cleared up the CEL for now.



1999 4runner SR5 2WD
3.4L
130k miles

BigBallsMcFalls

yeah, but if that is all you cleaned, you didn't clean it all

go down into the vertical opening and clean the 2 small wires
as shown in one of the pictures above