2000 C5 with codes P0171 AND P1431
Thread Starter
2nd Gear
Joined: May 2020
Posts: 2
Likes: 0
From: Mississippi, USA
2000 C5 with codes P0171 AND P1431
So, I just bought my first C5 about a week ago, and while bringing it home the fuel gauge went to zero on me. Always heard that was caused by sulfur build up, didn't think much of it besides making plans to keep the car fueled up and buy a few bottles of Techron when I find some. The guage comes and goes as to whether it wants to read or not this past week.
Well I took the car on a semi-long trip yesterday (80 miles one direction then back) and when I got home I noticed it felt like the car was having issues idling. Got out this morning, fired it up and everything seemed normal, started towards town to go fuel up and the check engine light came on/fuel guage zeros. Immediately turned around and parked it.
When I pulled the codes I got PCM codes P0171 (lean fuel bank 1) and P1431. My first instinct is to assume that the fuel pump or sending unit is going out but I won't pretend to be some sort of expert mechanic.
I know this seems to be a rather widespread issue but I'm new to C5's and my only previous experiences with Corvettes has been my C4. Anybody have any ideas?
Well I took the car on a semi-long trip yesterday (80 miles one direction then back) and when I got home I noticed it felt like the car was having issues idling. Got out this morning, fired it up and everything seemed normal, started towards town to go fuel up and the check engine light came on/fuel guage zeros. Immediately turned around and parked it.
When I pulled the codes I got PCM codes P0171 (lean fuel bank 1) and P1431. My first instinct is to assume that the fuel pump or sending unit is going out but I won't pretend to be some sort of expert mechanic.
I know this seems to be a rather widespread issue but I'm new to C5's and my only previous experiences with Corvettes has been my C4. Anybody have any ideas?
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,643
Likes: 4,082
From: Cape Coral, Florida
Welcome to the C5 Forum !!...if you could can you include in your profile any mods you may have and a tune if you know that...this helps us help you !!...as far as the P0171 it is bank specific so it would not be a fuel pump issue HOWEVER if the bank 2 long term fuel trims is close to 23 % but not above it which will illuminate the MIL you will need to get a scan tool on the car to see what both bank fuel trims look like percentage wise...if bank 2 is close we can have you look at the fuel trims while you increase the RPM to about 3000 for a few minutes...if the fuel trims decrease you have a vacuum leak somewhere...if they remain high it can be a fuel pump going bad leaning out both banks or even a dirty MAF sensor or even a dirty fuel filter...it could also be some clogged injectors on both banks too...with a dirty MAF you normally see both bank fuel trims negative and increase with RPM...scan tools are cheap these days and would be wise to get one depending on your budget but hey you bought a Corvette so you must have some "jingle"...LOL !!!...as far as the P1431 yes run some Techron but wait till the fuel gauge is 1/4 tank or so and then add it...that way it goes into the right tank where your issue is at...and it's always better to run ethanol free fuel if you can.
Last edited by C5 Diag; Aug 1, 2021 at 05:20 PM.
