midiwall

I have the Auterra and keep it with me in the truck all the time. It's come in handy on trail rides to help out other folks as well as keep tabs on what my truck is up to. I've used it for closed-loop tuning and mess with the dyno from time-to-time, but the cab gets kinda' busy with the Palm and a laptop up front. Most of the time I keep it in LIST mode and keep an eye on timing, ECT, LTFT, and STFT.

I also have this box: http://obddiagnostics.com/ which has done me well - the price is VERY right. The UI is "VBish" which is a bit of a turn-off, but... eh, it doesn't really hinder anything. The cool thing for folks like you is that Bev ("B. Rodman", the author) will sell you a pre-programmed PIC if you want to roll the rest yourself.

One of the guys I ride with has this box: http://www.obd-2.com/ The UI is nicer and handles well.

RuffRider

Well, looking at the specs my MAF is foobar. It is showing less air than it should hence the overlean condition. It should be 13-18 gm/sec at 2500rpm / no load. I am only seeing ~5-6 at that rpm.

Glad I checked :-)

RuffRider

Never mind... Scan tool is showing LB/M and the spec is in gm/sec... Mea culpa.

MTL_4runner

If you have the skills, then go for it!
.....I'll be happy to give the new Auterra interface a test drive.

I agree with Mark, those are the best scan tools (at a reasonable price) that I have seen. Seriously, if you are really that good then go ahead and write up a program for us (should only take like 5-10 minutes right? ......j/k). Most of us don't have that type of talent on tap (at least I know I don't as far as programming....I always hated those classes).

Back to sensors.....if both the MAF and O2 sensors are showing proper operating voltages and appear to be varying correctly under operation, then I would suggest that you might try pulling the negative terminal to see if the CEL clears. I have seen a few cases when just pulling the ECU fuse did not work and required pulling power temporarilly alltogether to force the ECU to relearn. https://www.yotatech.com/forums/f16/p0171-wont-go-away-help-56618/#post603102

Here is some more reading on troubleshooting OBD on Toyotas:
http://www.4x4wire.com/toyota/4Runner/tech/BR-3/
http://www.4x4wire.com/toyota/4Runner/tech/OBDII_ECU/

In 99% of the cases the MAF is at fault for the P0171 code on these vehicles but you may have the 1% where something else is amiss (may be a physical air leak somewhere after the MAF or any number of other alternatives mentioned in the above links)......something to keep in mind anyway.

RuffRider

Just a follow-up. I recleaned the MAF before I left town last week and have not had a code since. I'm going to wait until my Amsoil filter arrives before I put my new MAF sensor in.

As for the scan tools, I agree that Auterra is pretty good for the money. It just feels clunky to me (e.g. adding parameters to a graph, etc). If I give it a go I'll be sure to post a beta for feedback from the forum.

midiwall

I've been asking for them to at least add parameter storage for well over a year now. The thing that drives me nuts is having to re-add the list items (or graph items) each time that you start the app. I don't use my Palm for much of anything else, so it's "okay", but given that they already have storage for dyno setups, it seems silly to not allow list/graph sets to be stored.

99_Runner

So have you figured out what the problem was yet? My 4Runner just started throwing this same code so I'm wondering what to check. Also, does anyone know of a write up about cleaning the MAF?

midiwall

Searching the forum on "cleaning maf writeup" brought up a couple of hits. Checking the first one:
https://www.yotatech.com/forums/f2/maf-pictures-qs-45201/

Brought a link to here:
http://www.4x4wire.com/toyota/mainte...tenancep5.html

If your MAF is such that the element doesn't come out of the side, then check this thread from 4x4wire (also found in the old YT thread):
http://www.4x4wire.com/forums/showfl...&Number=106649

the_4runnin'_beast

precat...i didnt read all the replies but that could be a factor

DoubleZero4x4

I had the same code show up on my 2000 with 94K on it and the local Auto Zone ran the scan on it and said that it was my O2 sensor. Should I be cleaning my MAF when I replace the O2 sensor? I am a little hesitant about such a delicate instrument.

Thoughts...

the_4runnin'_beast

u dont HAVE to...

MTL_4runner

Do you have low miles on the O2 sensor (say less than 80k)?
Are you still getting decent gas mileage?

If the answer is yes to both then I wouldn't bother.....just clean the MAF.

DoubleZero4x4

I am suddenly getting 13mpg and I have 94K on the truck. I am thinking it is the O2 sensor cause I cleand the MAF and about 55 miles later the CEL came back on. The other day when I went to Auto Zone and had them read the codes, there were 3 distinct errors but I olny caught the code off of one which was the P0171. I am going to go back and this time get all three of the codes that the scanner caught.

MTL_4runner

That might change quite a bit......so there may be other issues that these symptoms as well.
Definately post all the code numbers when you get them.

DoubleZero4x4

Ok...I went back to Auto Zone and got the Codes...

There were three errors reported

P0130
P0133
P0171

So far all symptoms are still pointing to the forward O2 sensor.

Any thoughts or ideas would be appreciated.

MTL_4runner

Those first two codes (and possibly the third) are almost surely your front O2 (A/F on 99+) sensor.
The third code could be a MAF or an O2 sensor.....you may want to clean your MAF anyway.

DoubleZero4x4

I cleaned the MAF and I have ordered the URD O2 sensor. I will update the board when it arrives. My CEL usually comes back pretty quick (within a day). So if this new O2 sensor does not fix it, looks like I will be ordering a new MAF too.

DoubleZero4x4

For the benefit of those not looking at the other thread on this topic, here is my writeup on the O2 sensor replacement I did this weekend.

IS3004Runner

I have this same problem before, P0171. I fixed this issue by getting a used Maf from a junk yard, $50 from 02 ES300. Disconnected the battery to clear the ECU, put the new (used) MAF, and it's been working flawlessly since. I put 12k miles on it and I still get 18-20 mpg. No cel.

Just to let you know, on the old MAF, I cleaned it with an electronics cleaner but I still got CEL after driving a few miles. New maf cost $120 from the dealer so I got me a used one from junkyard.

cruzin1a

I got that code recently on my 99 4Runner. After reading online for a few days I read a hint posted on one of the sites concerning resolving the problem. This trouble code is set if you run out of gas. Go figure a few days before I ran out of gas, I know what can I say. Anyways I cleared the code and it has not returned. Sometimes it's a simple thing.

I'm sure you'll get it defined and fixed and we'll all be better for it, thanks