How To Clear A Check Engine Light With No Scan Tool

How To Clear A Check Engine Light With No Scan Tool


All Flat Rate Mechanic here and I
just want to do a quick video on how you
can clear your check engine light
without a scan tool
I actually got scan tool hooked up right
now just to show you guys what we have
as far as codes and things but um I’m
gonna tell you how to clear without a
scan tool and also a number of reasons
why and a lot of cases you shouldn’t
clear the check engine light so let’s get right into this I
got the scanner hooked up and first
we’re just looking at the monitors here
to see if all the monitors are set which
is basically a series of tests that your
computer goes through to make sure all
the systems are working right and it’s
all set we’re gonna go down see we got
four codes here we’ve got a p0456
for a very small evap leak and a
p0442 for a small small leak so we’re
gonna go ahead and try and clear these
without using the sand tool and all I’m
gonna do is go onto the hood here and
I’ve already loosened up these battery
terminals and we’re just gonna
disconnect them for oh I’d say about a
minute and also it’s a good idea a lot
of times these cables don’t reach but
you can sort them out short them out
with a wrench or something with it like
they do here and what that’s gonna do is
this actually gonna it’s gonna drain the
power that may be stored in the computer
or anything like that so the short those
out briefly leave this disconnected for
about a minute which I’m gonna do and
we’ll be right back alright so we had
the battery disconnected for a little
over a minute we shorted out the wrench
just to drain all the power that may be
stored in any of the computers now just
a word advice this does not work on all
vehicles it works on most older
model vehicles where this one is a
little newer it may not even work so
let’s go in here start it up and see if
the check engines light is gone
all right so as you can see that did
work now what we’re gonna find on the
scanner I’ll show you guys
I’ll also leave a link below where you
can get this little handheld scanner
comes in real handy alright so by
disconnecting the battery for a minute
and we did get our check engine light
clear but I’ll show you what happens
after we do that as soon as we get
connected here alright so now you can
see we’re looking at these emissions
monitors it says IM monitors DTC’s
cleared we’re looking at these monitors
and they’re already in complete the i NC
means incomplete mins means none of
these tests have run now what happens
when none of these tests have been run
if you go in for admissions test or
something like that even though your
check engine light is off it’s still
going to fail the admission test until
all these until all these monitors have
passed and if they haven’t passed that’s
when it’s going to set code now also a
lot of times when you’re going to buy a
vehicle if you’re buying a used vehicle
and they’re you know the sellers a
little sketchy they may have went in and
cleared the check engine light and that
light’s not going to come back on until
these tests are set so you may purchase
a vehicle with no check engine light and
then you drive down the road and the
light pops on so if you are buying a
new vehicle it’s always a good idea to
have one of these little handheld
scanners and you can plug it in and you
can look at the monitors and see if they
have set if they have not set then that
means they probably cleared the light
and there’s probably a problem in the
emission system somewhere so always be
aware of that also if you have a check
engine light and you plan on bringing it
to get repaired you definitely do not
want to clear that light before you
bring it to the repair shop because you
bring it in and they’re not gonna have
any information to go by or a code I
mean unless you write that code down
prior to clearing it which is something
you probably always want to do that’s
why one of these little handheld
scanners comes in real handy because
it’s not a bad idea to clear the code
and drive the vehicle just to make sure
it wasn’t it wasn’t a fluke or something
like in this case we have some evap
codes so it’s possible you know the
customer may have just let the gas cap
loose or something along those lines so
in a case like this it would always be a
good idea to clear the code and drive
it and see if the check engine light comes back if it does
come back then you’re gonna want to
leave that light on
until you get a looked at that way the
technician looking at it has information
to go by because if you guys if it gets
cleared then I really have nothing to go
by and they won’t be able to fix it but
that about does it for this video guys
if it was helpful
be sure to hit the thumbs up button
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thanks

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