How To Clear A Check Engine Light With No Scan Tool - YouTube

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

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