rev up your engines, today I'm going to show you how to fix a car in this case
of this lexus when a bunch of trouble lights come on in the dash, in this case it's got the
check engine light it's got track off, maintenance required, check vehicle
speed control, and this giant one here that just tells you warning something
wrong as I happening so we start with a simple thing, we plugged the scan tool
under the dash in this case it just goes onto here and plugs right in here then
they have the key on the on position with the lights on, but the engine not
running, then we let the scan tool do its thing it takes a minute or so and lo and
behold this baby's got 14 different codes now the first thing we wanted to
do is look at the P codes those are the codes that have to do with the
running of the car, it's PL 171 174 then 1 7 174 which then we know those are
real serious codes then there's the C codes, now we're going to
start with the P codes because the P codes
will make this vehicle not pass the state emissions test, the customer wants
it to pass the emission tests, he knows it's an old car it's almost got 200,000
miles on it he wants it so it'll run decent and pass the emissions test and I
know for a fact on these lexus says they have strange software all the Toyotas do
that if you get a P code the check engine light comes on but often that
turns the traction control system off automatically by software, so you get the
track off light in this case there probably isn't a failure in the track
system, it's just the check engine system is making that trip the code, now this is
a v8 engine so it's got number one side and number two side but both sides are
running lean they either have too much air or not enough fuel let's hope it's a
vacuum leak something that's relatively simple to find, but I'm not all that
hopeful it's going to be a vacuum leak and here's why, I looked at the freeze
frame data and it shows that the P0 one-seven-one code occurred at 63 miles
an hour and then I checked the pl 174 code it also tripped at 63 miles an hour
so the code tripped at a relatively higher speed vacuum leaks affected engine the
most at low speeds when the engines barely going you got a vacuum leak
that's gonna affect the air fuel ratio a lot more when you're going slow than
when you're going fast normally with a vacuum leak you'll get the freeze frame
data showing the car was going slow but if there's a problem in the fuel system
itself not sending enough fuel that'll generally hurt her at a higher
speed but we're gonna check for broken parts anyways you never know what could
have come off or gotten loose, so we'll take the stupid cover off it and as I look
around there's no obviously broken hoses or connectors, so go to the air filter
assembly check that, get the clips off and welcome take it out not much working
room, it does have a leaf in it but it's pretty clean that's not a problem, but
this mass airflow sensor it could be dirty, so let's take it off
they're often hard to take off so I get a long pair of pliers squeeze it try to
pop it off it can be a real pain in the butt, then we unscrew the thing
to a little screws they often stick so push down real hard you don't want to
strip them out, there it comes, now these sensors can often get dirty I can see
there's a reasonable amount of dirt on the little part here and then there's an
inside part so we're gonna clean it, and when you do only use mass airflow sensor
cleaner, you just spray it that's cleaning the part that you can't see
turn it over, spray it then there's stuff inside, you spray that one way and then
the other you want to get it nice and clean, then you want the thing to air dry
for about half an hour, you don't want any residual stuff to be sucked in, or any
cleaner left on here, this stuff evaporates off, doesn't leave any residue
that's why you have to use the mass airflow sensor
don't use carburetor cleaner, then after half an hour put it back in
and put the screws in the holder place then plug the connector back in never
clean up with the connector in, you don't want any power going to it when you're
cleaning it, it snapped to cover back on and put the stupid beauty cover back on
then, we'll take you for a spin, we know the code came on at 63 miles an
hour, so we're gonna go drive at 63 miles an hour, well here goes nothing well
let's hope it's something, and I've also reset all the lights so all those warnings
that were on before are all gone, now you're do want to go for a good 20 30
minute road test to really run it through to make sure it's testing
everything, well now the road test is over and all those nasty lights haven't
come back on, let's get the scan tool and see what it says
it's doing its thing, look at that now there's no codes at all, even though we
didn't work on the traction control system the code didn't come back because
as I said in these things if you get a check engine light come on, that will often
turn the ABS off it'll turn the traction control off, even though there's
nothing wrong with those systems it's a software thing, that if the car isn't
running right it won't let it operate those systems, so now thanks to the Handy
scan tool and the ability to have freeze frame data, you always want a scan tool
that can record the freeze frame data, so when there's a trouble code it'll show
you exactly when it occurred and all the data that were around then when it did
occur to fix it right, because as a warning to anyone, when you get an old
car like that fixed and it's ready for inspection, take it in and get it
inspected, cuz you never know what some other electronic thing is gonna go wrong
and if it runs fine and it's got a little light on, what the heck you can
drive at another year until its inspection time again, so if you never
want to miss another one of my new car repair videos, remember to ring that Bell!