check engine lite
Thread Starter
Racer
Joined: Sep 2016
Posts: 262
Likes: 29
From: Parrish florida
check engine lite
hi all, returned from a month long trip to n.h. left the car on a battery tender.
fired it up took it for a spin and the check engine lite came on. went into the DIC and got a couple of codes
code171H and 174H, indicating lean fuel both banks. I cleared the codes and added a fuel additive.
took it for another spin it ran fine
but the engine lite came on.
has any one experienced this happening ? any tips on what to do will b greatly appreciated thanks espy
fired it up took it for a spin and the check engine lite came on. went into the DIC and got a couple of codes
code171H and 174H, indicating lean fuel both banks. I cleared the codes and added a fuel additive.
took it for another spin it ran fine
but the engine lite came on.
has any one experienced this happening ? any tips on what to do will b greatly appreciated thanks espy
Thread Starter
Racer
Joined: Sep 2016
Posts: 262
Likes: 29
From: Parrish florida
c5 engine lite
hi Joe, I have a scan tool and haven't used it only because I thought the DIC would give me the same info. I'm gonna plug in and run the diagnosis thru it. hopefully that's all it is.
ps at one point she was running very rough at idle but still had great throttle response and plenty of power. when I stopped at a lite it was idling smooth.
(something I should ve mentioned in my original post)
ps at one point she was running very rough at idle but still had great throttle response and plenty of power. when I stopped at a lite it was idling smooth.
(something I should ve mentioned in my original post)
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,314
Likes: 3,927
From: Cape Coral, Florida
This is one of the top 3 DTC’s for any car so it’s not uncommon !!…with both banks lean it could be vacuum leak, fuel delivery or even a dirty MAF….have you had the intake bellows or intake manifold off for any reason or any recent maintenance been done ??…run the car at idle and let us know what your long and short term fuel trims look like…your long terms are most likely over 20%….run the engine at 3000 RPM for a few minutes and see if the fuel trims decrease…the long terms take a few minutes…if they decrease you have a vacuum leak…also let us know what your MAF sensor reads…with a dirty MAF you will see negative fuel trims at idle but increase at higher RPMS…adding fuel system cleaner wouldn’t do anything for you unless you had some clogged injectors…you would most likely see misfires with this !!…also with a vacuum leak the car runs bad at idle but better at higher RPM…intake vacuum is less at higher loads so
a vacuum leak has less of an effect…you have less of a leak !!
a vacuum leak has less of an effect…you have less of a leak !!
Last edited by C5 Diag; Oct 27, 2021 at 06:48 PM.
