P0171 Code and MAF sensor
#1
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P0171 Code and MAF sensor
I finally got around to cleaning the MAF sensor after having my check engine lamp come on a few weeks ago when pulling up a long hill at 75mph in 5th with the cruise on.
The check engine lamp would reset itself by the next moring but come on again after pulling another long hill. The scanner at Autozone gave a P0171 - bank 1 too lean code.
Removing the MAF, the temp sensor was clean but the airflow sensor wires were black. A little contact cleaner and some q-tips and I now have shiny sensor wires again.
Lets hope this fixes the lean code I was getting...
The check engine lamp would reset itself by the next moring but come on again after pulling another long hill. The scanner at Autozone gave a P0171 - bank 1 too lean code.
Removing the MAF, the temp sensor was clean but the airflow sensor wires were black. A little contact cleaner and some q-tips and I now have shiny sensor wires again.
Lets hope this fixes the lean code I was getting...
#2
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Originally posted by mark_fit
I had the same problem. No light since i cleaned it.
I think the black stuff could have been oil from a K&N air filter. If you have one. GOOD LUCK!
I had the same problem. No light since i cleaned it.
I think the black stuff could have been oil from a K&N air filter. If you have one. GOOD LUCK!
Checking and cleaning the MAF is sure a no-brainer. Probably a good thing to do every 30K service...
#3
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Since you've got the intake tube open to get to the MAF, it'd be a good idea to clean out the throttle body as well. You'll be amazed at how much goop you'll get out of there. Info is here on "dukestr"'s website:
http://www.thedukenetwork.net/4runner
Pick "Maintenance" then "Throttle Body" from the top line menu
http://www.thedukenetwork.net/4runner
Pick "Maintenance" then "Throttle Body" from the top line menu
#4
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Re: P0171 Code and MAF sensor
Originally posted by JSharp
I finally got around to cleaning the MAF sensor after having my check engine lamp come on a few weeks ago when pulling up a long hill at 75mph in 5th with the cruise on.
The check engine lamp would reset itself by the next moring but come on again after pulling another long hill. The scanner at Autozone gave a P0171 - bank 1 too lean code.
Removing the MAF, the temp sensor was clean but the airflow sensor wires were black. A little contact cleaner and some q-tips and I now have shiny sensor wires again.
Lets hope this fixes the lean code I was getting...
I finally got around to cleaning the MAF sensor after having my check engine lamp come on a few weeks ago when pulling up a long hill at 75mph in 5th with the cruise on.
The check engine lamp would reset itself by the next moring but come on again after pulling another long hill. The scanner at Autozone gave a P0171 - bank 1 too lean code.
Removing the MAF, the temp sensor was clean but the airflow sensor wires were black. A little contact cleaner and some q-tips and I now have shiny sensor wires again.
Lets hope this fixes the lean code I was getting...
With the code on, would you lose power big time at full throttle?
I'm having the same code and I've cleaned the MAF, throttle body, and checked for vacuum leaks. I just told the stealer to get me an O2 sensor (in front of cat). I hope that fixes it.
#5
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Re: Re: P0171 Code and MAF sensor
Originally posted by dragr1
With the code on, would you lose power big time at full throttle?
I'm having the same code and I've cleaned the MAF, throttle body, and checked for vacuum leaks. I just told the stealer to get me an O2 sensor (in front of cat). I hope that fixes it.
With the code on, would you lose power big time at full throttle?
I'm having the same code and I've cleaned the MAF, throttle body, and checked for vacuum leaks. I just told the stealer to get me an O2 sensor (in front of cat). I hope that fixes it.
You may need a new MAF if cleaning does not help.
#7
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Originally posted by dragr1
Anyone else? Throttle position sensor maybe?
Anyone else? Throttle position sensor maybe?
http://www.4x4wire.com/forums/showfl...5&o=14&fpart=1
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#8
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If you have a junkyard near you I would see if they let you borrow another MAF (must be 99-02) to try out in the parking lot (only takes 2 secs to put one in). I remember someone in your exact same situation on Yotatech that even cleaned theirs with electrical contact cleaner to no avail. I really don't think it is the TPS and only has a small possibility in my book of being an O2 sensor but you never know.
The lean condition is almost always associated with the MAF:
https://www.yotatech.com/forums/show...ht=replace+maf
......unless you have a supercharger!
EDIT: Also did a bit of searching and forgot on 99+ tucks the front O2 sensor (bank 1, sensor 1) is actually an A/F ratio sensor not just a traditional O2 sensor like on the 96-98's. Here is someone who did have the same problem and the A/F sensor did the trick.....check it out.
https://www.yotatech.com/forums/show...ighlight=po171
Try using the search button, there is tons of stuff in there on this subject.
The lean condition is almost always associated with the MAF:
https://www.yotatech.com/forums/show...ht=replace+maf
......unless you have a supercharger!
EDIT: Also did a bit of searching and forgot on 99+ tucks the front O2 sensor (bank 1, sensor 1) is actually an A/F ratio sensor not just a traditional O2 sensor like on the 96-98's. Here is someone who did have the same problem and the A/F sensor did the trick.....check it out.
https://www.yotatech.com/forums/show...ighlight=po171
Try using the search button, there is tons of stuff in there on this subject.
Last edited by MTL_4runner; 01-11-2004 at 08:38 AM.
#9
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Originally posted by MTL_4runner
If you have a junkyard near you I would see if they let you borrow another MAF (must be 99-02) to try out in the parking lot (only takes 2 secs to put one in). I remember someone in your exact same situation on Yotatech that even cleaned theirs with electrical contact cleaner to no avail. I really don't think it is the TPS and only has a small possibility in my book of being an O2 sensor but you never know.
The lean condition is almost always associated with the MAF:
https://www.yotatech.com/forums/show...ht=replace+maf
......unless you have a supercharger!
EDIT: Also did a bit of searching and forgot on 99+ tucks the front O2 sensor (bank 1, sensor 1) is actually an A/F ratio sensor not just a traditional O2 sensor like on the 96-98's. Here is someone who did have the same problem and the A/F sensor did the trick.....check it out.
https://www.yotatech.com/forums/show...ighlight=po171
Try using the search button, there is tons of stuff in there on this subject.
If you have a junkyard near you I would see if they let you borrow another MAF (must be 99-02) to try out in the parking lot (only takes 2 secs to put one in). I remember someone in your exact same situation on Yotatech that even cleaned theirs with electrical contact cleaner to no avail. I really don't think it is the TPS and only has a small possibility in my book of being an O2 sensor but you never know.
The lean condition is almost always associated with the MAF:
https://www.yotatech.com/forums/show...ht=replace+maf
......unless you have a supercharger!
EDIT: Also did a bit of searching and forgot on 99+ tucks the front O2 sensor (bank 1, sensor 1) is actually an A/F ratio sensor not just a traditional O2 sensor like on the 96-98's. Here is someone who did have the same problem and the A/F sensor did the trick.....check it out.
https://www.yotatech.com/forums/show...ighlight=po171
Try using the search button, there is tons of stuff in there on this subject.
#10
Contributing Member
Might want to pull the MAF out again and clean with some warm water and dishsoap.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
#11
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iTrader: (3)
Originally posted by MTL_4runner
Might want to pull the MAF out again and clean with some warm water and dishsoap.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
Might want to pull the MAF out again and clean with some warm water and dishsoap.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
#13
Contributing Member
Originally posted by dragr1
I borrowed another MAF briefly and it definitely seemed to help. So today I traded my stock front bumper for a MAF and to sweeten the deal, I also got both O2 sensors and a TPS, woohoo. One of these should cure the problem. I'll do them one at a time, starting with the MAF and let you know what comes about. For good measure, do you think I should clean the MAF before installing, it's got a little dust on it. If so-water, throttle body cleaner, or Radio Shack electrical parts cleaner?
I borrowed another MAF briefly and it definitely seemed to help. So today I traded my stock front bumper for a MAF and to sweeten the deal, I also got both O2 sensors and a TPS, woohoo. One of these should cure the problem. I'll do them one at a time, starting with the MAF and let you know what comes about. For good measure, do you think I should clean the MAF before installing, it's got a little dust on it. If so-water, throttle body cleaner, or Radio Shack electrical parts cleaner?
#15
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ive tried both throttle body/carb cleaner and electric contact cleaner. throttle body cleaner seems to leave a very light oily residue. contact cleaner leaves a very very faint dry residue. I doubt either residue is going to throw off the readings but i like to try and remove the residue afterwards with a cloth or something.
i havent used water and soap becuase im afraid of it not drying all the way very quickly. but thats just because im impatient.
i havent used water and soap becuase im afraid of it not drying all the way very quickly. but thats just because im impatient.
#16
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Originally posted by kimchee
ive tried both throttle body/carb cleaner and electric contact cleaner. throttle body cleaner seems to leave a very light oily residue. contact cleaner leaves a very very faint dry residue. I doubt either residue is going to throw off the readings but i like to try and remove the residue afterwards with a cloth or something.
i havent used water and soap becuase im afraid of it not drying all the way very quickly. but thats just because im impatient.
ive tried both throttle body/carb cleaner and electric contact cleaner. throttle body cleaner seems to leave a very light oily residue. contact cleaner leaves a very very faint dry residue. I doubt either residue is going to throw off the readings but i like to try and remove the residue afterwards with a cloth or something.
i havent used water and soap becuase im afraid of it not drying all the way very quickly. but thats just because im impatient.
#17
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Originally posted by MTL_4runner
Might want to pull the MAF out again and clean with some warm water and dishsoap.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
Might want to pull the MAF out again and clean with some warm water and dishsoap.
If there is any residue on the MAF sensor it may not function correctly.
Just another thought.
#18
Contributing Member
Originally posted by dragr1
I found a MAF at a junkyard and finally replaced my MAF today. I drove around for about 30 miles and so far it seems much better. I hope it stays that way. Thanks for all the help!
I found a MAF at a junkyard and finally replaced my MAF today. I drove around for about 30 miles and so far it seems much better. I hope it stays that way. Thanks for all the help!
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