Mike "Wuzzy121". Rest in peace, brother

Go Back   Tacoma World Forums > Tacoma Discussion > 1st Gen. Tacomas

Notices

p0171 code

Reply
 
Referenced Products Thread Tools Search this Thread
Old 10-12-2012, 09:31 AM   #1
spider22 [OP] spider22 is offline
Junior Member
spider22 is on a distinguished road
Joined: Oct 2012, #88833
Gender: Male
Posts: 4
spider22's Tacoma Gallery
p0171 code

Have a 2003 Prerunner. Engine light came on a couple days ago. I took it to auto store to put on computer. The computer read a p0171 trouble code, which is System too Lean (Bank 1). I bought some cleaner to clean the MAF sensor, but engine light stayed on, so I bought a new sensor and replaced it. Light is still on. This whole time my truck is running fine, not sluggish nor missing. Any ideas??

Spider22
  Reply With Quote
Old 10-12-2012, 02:35 PM   #2
Senior Member
Hawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant futureHawaiian05 has a brilliant future
 
Hawaiian05's Avatar
Name: Tony
Joined: Aug 2012, #84019
Location: Boise, ID/ Hawaii
Gender: Male
Posts: 292
Hawaiian05's Tacoma Gallery
Just checking, you did clear the code once you cleaned and /or replaced the sensor, right?
Did you check for any leaks near/around the intake hose or airbox? I've seen a few in the past in which either a vacuum hose was disconnected or the plastic air tube was loose. I've also seen cracked airboxes, which caused an air leak or a "lean" code. Do a thorough visual check first before you do anything else...
  Reply With Quote
Old 10-12-2012, 09:21 PM   #3
ASE Master Tech
BamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shedBamaToy1997 is one of the sharper tools in the shed
 
BamaToy1997's Avatar
Marines: M1A2 hull/turret technician, 4th Maint Btn. 4th FSSG.
Name: Bill
Joined: Jan 2012, #71846
Location: Marion, AL
Age: 46
Gender: Male
Posts: 8,098
BamaToy1997's Tacoma Gallery
A p0171 can be stored for a lot more reasons that a dirty/failed MAF sensor. There are several possible issues that you need to address. Vacuum leaks, injector issues, O2 sensor issue, fuel pump issue (less likely since it is only one bank, but the other side could be right on the brink of code) I would get a data reader and check your fuel trim numbers. Are they severe? (+20% or more) or just enough to set a code (Sometimes as low as 7%) Otherwise you will be looking at throwing parts at it. Find the failure. try reading trim data then carefully spray a product like brake clean around the intake manifold and vacuum hoses. If the fuel trim suddenly shoots the other direction (rich) then you have found the area at fault.
  Reply With Quote
Old 10-15-2012, 04:15 PM   #4
spider22 [OP] spider22 is offline
Junior Member
spider22 is on a distinguished road
Joined: Oct 2012, #88833
Gender: Male
Posts: 4
spider22's Tacoma Gallery
Took truck back to get p0171 code cleared, now along with p0171, the computer also got p0113 and p0102 codes. Truck still running smooth. I did try to unplug MAF sensor while truck was running and it killed. So I would think that it is getting correct voltage to it. The other two codes show a possible cause being ECM has failed. What now?

Spider22
  Reply With Quote
Old 10-15-2012, 04:23 PM   #5
RAT Products
isu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shed
 
isu2014's Avatar
Name: Ryan
Joined: Apr 2010, #35140
Location: Ames, IA
Age: 23
Gender: Dude
Posts: 10,686
isu2014's Tacoma Gallery
Try some of this maybe? http://shop.advanceautoparts.com/web...-crc_7040065-p
Personally I would keep driving it if there aren't any drivability issues. Could pull the ECM fuse and reset it, maybe it glitched.
  Reply With Quote
Old 10-15-2012, 04:31 PM   #6
:POOPCORN:
98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed
 
98tacoma27's Avatar
Marines:
Name: Ben
Joined: Dec 2008, #11714
Location: Beech Creek
Gender: Dude
Posts: 48,263
98tacoma27's Tacoma Gallery
Quote:
Originally Posted by spider22 View Post
Took truck back to get p0171 code cleared, now along with p0171, the computer also got p0113 and p0102 codes. Truck still running smooth. I did try to unplug MAF sensor while truck was running and it killed. So I would think that it is getting correct voltage to it. The other two codes show a possible cause being ECM has failed. What now?

Spider22
You blew the fuse when you disconnected the MAF with it running.

http://www.ncttora.com/fsm/2003/Repa...e/cip01001.pdf

http://www.ncttora.com/fsm/2003/Repa...e/cip01101.pdf
  Reply With Quote
Old 10-15-2012, 06:34 PM   #7
Senior Member
Robertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shed
 
Robertgeejr1's Avatar
Name: Robert
Joined: Dec 2011, #69167
Location: Aorora, Ill, yeah!
Gender: Male
Posts: 776
Robertgeejr1's Tacoma Gallery
one easy way to clear the codes, is to just disconnect the neg. battery cable and just let her rest for 30 mins to one hour.
be careful discounting things while the truck is running the last thing you want to do is to cause a backfire or two. that could lead to more problems.
  Reply With Quote
Old 10-16-2012, 05:17 PM   #8
spider22 [OP] spider22 is offline
Junior Member
spider22 is on a distinguished road
Joined: Oct 2012, #88833
Gender: Male
Posts: 4
spider22's Tacoma Gallery
Ok, this is what I did. I checked ECM fuse which I believe is the EFI fuse. It is good.I disconnected negative side of battery to try and clear code. In the process I noticed that the negative lead from the battery to chasis ground was broke. I reattached it and connected battery back. I started engine and check engine light is off. Coincidence??

Spider
  Reply With Quote
Old 10-16-2012, 05:22 PM   #9
:POOPCORN:
98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed
 
98tacoma27's Avatar
Marines:
Name: Ben
Joined: Dec 2008, #11714
Location: Beech Creek
Gender: Dude
Posts: 48,263
98tacoma27's Tacoma Gallery
No coincidence. It only takes a few seconds to clear the codes with the battery disconnected. The EFI fuse is under the hood. The ECU fuses are in the cab.

http://www.ncttora.com/fsm/2003/Wiri...c/relayloc.pdf
  Reply With Quote
Old 10-16-2012, 06:13 PM   #10
Senior Member
Robertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shedRobertgeejr1 is one of the sharper tools in the shed
 
Robertgeejr1's Avatar
Name: Robert
Joined: Dec 2011, #69167
Location: Aorora, Ill, yeah!
Gender: Male
Posts: 776
Robertgeejr1's Tacoma Gallery
Quote:
Originally Posted by 98tacoma27 View Post
No coincidence. It only takes a few seconds to clear the codes with the battery disconnected. The EFI fuse is under the hood. The ECU fuses are in the cab.

http://www.ncttora.com/fsm/2003/Wiri...c/relayloc.pdf
I know you are going to argue with everything I say, but from everything I have read over many, many years, it is advised to disconnect the neg. cable for 30 mins.
  Reply With Quote
Old 10-16-2012, 07:09 PM   #11
RAT Products
isu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shedisu2014 is one of the sharper tools in the shed
 
isu2014's Avatar
Name: Ryan
Joined: Apr 2010, #35140
Location: Ames, IA
Age: 23
Gender: Dude
Posts: 10,686
isu2014's Tacoma Gallery
Quote:
Originally Posted by Robertgeejr1 View Post
I know you are going to argue with everything I say, but from everything I have read over many, many years, it is advised to disconnect the neg. cable for 30 mins.
I've only heard this rule in regards to working with airbags. I always used to reset my check engine light by pulling the efi fuse.
  Reply With Quote
Old 10-17-2012, 05:30 AM   #12
:POOPCORN:
98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed98tacoma27 is one of the sharper tools in the shed
 
98tacoma27's Avatar
Marines:
Name: Ben
Joined: Dec 2008, #11714
Location: Beech Creek
Gender: Dude
Posts: 48,263
98tacoma27's Tacoma Gallery
Quote:
Originally Posted by isu2014 View Post
I've only heard this rule in regards to working with airbags. I always used to reset my check engine light by pulling the efi fuse.
X2. I use a reader or the Ultragauge to reset. I only resort to the neg cable when I don't have access to a reader. And when I pull the cable, I wait about a minute to let any capacitors discharge.
  Reply With Quote
Old 10-17-2012, 06:14 PM   #13
spider22 [OP] spider22 is offline
Junior Member
spider22 is on a distinguished road
Joined: Oct 2012, #88833
Gender: Male
Posts: 4
spider22's Tacoma Gallery
Took truck to work today. It ran fine. Check engine light is still off. Thanks for the help.
  Reply With Quote
Old 06-28-2014, 08:35 PM   #14
KJW KJW is offline
Junior Member
KJW will become famous soon enough
Joined: Feb 2010, #31620
Location: SoCal
Gender: Male
Posts: 16
KJW's Tacoma Gallery
Infamos PO171 Code.....What Worked for Me

Just sold a '99 Tacoma with 175,000 miles that would not pass smog due to PO171. Truck runs smooth and gives no indication of vacum leaks. After reading and hearing all sorts of stories I did the following:
Wasted time and money letting Toyota clean the MAF and get the voltage reading correct according to them. Failed again on PO171. They just said.....Sorry.
Then I brought it home and did a complete visual on the engine vacum lines and pulled out the air cleaner box to clean and check for cracks.....non found......went to AutoZone bought a new sensor for $80 put everything back together and drove the truck for 30 miles mixed freeway and street.
Past smog with no problems same afternoon.

Toyotas seem to get hit hard with this code and you can waste a lot of time chasing it. The above worked for me pretty quickly.

kjw
  Reply With Quote
Reply

Products Discussed in this Thread

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Code P0171 Flaadog Technical Chat 10 10-28-2011 05:58 AM
CEL CODE P0171 harley09 Technical Chat 28 10-13-2010 11:38 AM
P0171 Code shaniac 1st Gen. Tacomas 9 08-18-2010 09:19 PM
P0171 code help needed crazyscout Technical Chat 2 06-25-2010 07:29 AM
code p0171 trailinTaco 1st Gen. Tacomas 1 06-23-2009 08:23 PM


Copyright © 2014 Tacoma Forum. Tacoma World is not owned by, or affiliated with Toyota Motor Corporation.