New to this forum.
Thread Starter
Driver School Candidate
Joined: Aug 2010
Posts: 28
Likes: 0
From: SL, UT
New to this forum.
So I recently bought my wife a '99 RX 300 and on the drive home noticed the CEL came on with a P0171 lean on bank 1 code. I have already cleaned the MAF and have heard that there are a few other sensors that are notorious on these cars to cause this code. My question for any/all of you is what have you done when getting this code to resolve it to narrow down this issue.
I come from the VW/Audi world where we have Vag-Com to easily diagnose whats wrong, but I cant seem to find any decent software for these cars. Thanks guys.
I come from the VW/Audi world where we have Vag-Com to easily diagnose whats wrong, but I cant seem to find any decent software for these cars. Thanks guys.
Lexus Test Driver
Joined: Aug 2009
Posts: 5,724
Likes: 114
From: NJ
Not everybody knows the answer to every question thats asked, but we try our best. Patience is the main ingredient in solving a problem!
I would start by cleaning the throttle body, and the IACV and go easy on the screws because they are extremely soft.
DIY: https://www.clublexus.com/forums/rx-...-write-up.html
I would start by cleaning the throttle body, and the IACV and go easy on the screws because they are extremely soft.
DIY: https://www.clublexus.com/forums/rx-...-write-up.html
Lexus Test Driver
Joined: Aug 2009
Posts: 5,724
Likes: 114
From: NJ
Run some fuel injector cleaner through it, it may be a injector blockage or low pressure. Is the exhaust leaking anywhere making the A/F ratio go "crazy". If you changed the air filter recently, there a few air intake lines on the box in which the air filter is located, you may want to check those. If your still running lean, check the spark plugs, check the o2 sensor's, and check the a/f sensor.
If this is too much, head on over to your local trusty mechanic, seeing as though you come from Audi and VW this can't be anything compared to that...lol
If this is too much, head on over to your local trusty mechanic, seeing as though you come from Audi and VW this can't be anything compared to that...lol
Pole Position
Joined: Sep 2006
Posts: 3,054
Likes: 103
From: Sacramento, California
Thread Starter
Driver School Candidate
Joined: Aug 2010
Posts: 28
Likes: 0
From: SL, UT
Run some fuel injector cleaner through it, it may be a injector blockage or low pressure. Is the exhaust leaking anywhere making the A/F ratio go "crazy". If you changed the air filter recently, there a few air intake lines on the box in which the air filter is located, you may want to check those. If your still running lean, check the spark plugs, check the o2 sensor's, and check the a/f sensor.
If this is too much, head on over to your local trusty mechanic, seeing as though you come from Audi and VW this can't be anything compared to that...lol
If this is too much, head on over to your local trusty mechanic, seeing as though you come from Audi and VW this can't be anything compared to that...lol
Trending Topics
This is just one possibility. I had the exact code on my 2000 and changed the MAF sensor and that was three months ago and the light has not come back on. The Toyota dealer said this is a common sensor to go in that time frame. It is very easy to do and I recommend replacing rather than cleaning. I tried the cleaning with no effect. As soon as I replaced it the light went away.
ClubLexus Stories
Celebrating Lexus & Toyota from Around the Globe
Top 10 Most Confusing Things Lexus Has Ever Done!
Joe Kucinski
2026 Lexus ES Review: Lexus Re-Embraces Founding Principles
Michael S. Palmer
10 Lexus Bargains That are Cheaper Than a New Toyota RAV4
Joe Kucinski
8 Weirdest Things Lexus Has Ever Built
Verdad Gallardo
10 Lexus Designs That Have Aged Like Fine Wine
Verdad Gallardo
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!
Michael S. Palmer
10 Best Lexus Models No One Remembers
Joe Kucinski
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing
Michael S. Palmer
Top 10 Lexus & Toyotas to Drive Before You Die!
Joe Kucinski
Thread Starter
Driver School Candidate
Joined: Aug 2010
Posts: 28
Likes: 0
From: SL, UT
Thread
Thread Starter
Forum
Replies
Last Post
