Error code P0171 - lean bank 1
#1
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Error code P0171 - lean bank 1
I received this error and changed the MAF sensor. The CEL and VSC Off light came on again shortly after but has not come on again in the over six months since I unplugged the battery. I have driven the car only three or four thousand miles since and not much on the highway. (The VSC Off light came on one other time about four months ago but has not come on again even though I did not do anything.)
Should I assume that the issue is resolved?
I have the same trip of a few hundred highway miles on which the light came on in the first place and would like to try to make it is resolved beforehand.
Thank you.
1999 ES300
Should I assume that the issue is resolved?
I have the same trip of a few hundred highway miles on which the light came on in the first place and would like to try to make it is resolved beforehand.
Thank you.
1999 ES300
#2
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Join Date: Nov 2008
Location: PA>FL>JP>WA>JP>WA
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do you have an aftermarket intake?
i know that with my aftermarket exhasut system i was getting code for the 02 sensor and then i switched to the O2 simulator and upgraded to a high flow filter, in which whenever i drive on the highway and let me car coast (5 spd) in neutral it dies down and once in a while i get a fault code for to lean.
and another suggestion is going to autozone and getting them to use an OBD scanner to check if the code is still there and if they can find any other codes, and delete those
i know that with my aftermarket exhasut system i was getting code for the 02 sensor and then i switched to the O2 simulator and upgraded to a high flow filter, in which whenever i drive on the highway and let me car coast (5 spd) in neutral it dies down and once in a while i get a fault code for to lean.
and another suggestion is going to autozone and getting them to use an OBD scanner to check if the code is still there and if they can find any other codes, and delete those
#4
Maintenance Moderator
iTrader: (2)
generally, a single lean bank doesn't point to the mass air flow sensor - it typically points to an intake gasket leak, injector problem, or bad o2 sensor...
but, this is a generalization and definitely not the rule...
as RT said, get a decent scanner and see if there are any pending codes...
but, this is a generalization and definitely not the rule...
as RT said, get a decent scanner and see if there are any pending codes...
#5
Lexus Test Driver
iTrader: (22)
I received this error and changed the MAF sensor. The CEL and VSC Off light came on again shortly after but has not come on again in the over six months since I unplugged the battery. I have driven the car only three or four thousand miles since and not much on the highway. (The VSC Off light came on one other time about four months ago but has not come on again even though I did not do anything.)
Should I assume that the issue is resolved?
I have the same trip of a few hundred highway miles on which the light came on in the first place and would like to try to make it is resolved beforehand.
Thank you.
1999 ES300
Should I assume that the issue is resolved?
I have the same trip of a few hundred highway miles on which the light came on in the first place and would like to try to make it is resolved beforehand.
Thank you.
1999 ES300
#7
Lexus Champion
Agree with RT and Mitsu. A good scan tool that can read the freeze frame data. For P0171 you need to look at the total fuel trim(short and long term combined) it should be close to zero. If it's close to zero then your MAF is o.k, now look for the reading of the A/F or O2 sensors. Make sure you check the O2 sensor 2(the one after the cat).
If you see the total fuel trim bank 2 or bank 1 let's say " +34%" that's mean your MAF is bad.
If you see the total fuel trim bank 2 or bank 1 let's say " +34%" that's mean your MAF is bad.
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