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328: Why Won't This F@%$'n Key Program?! Vol 2
328: Why Won't This F@%$'n Key Program?! Vol 2
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About this episode
Dive into the challenges of key programming with two tricky cases: a 2017 Toyota Camry and a 2018 Chevy Malibu. The Camry's issue stemmed from a missing ignition key switch and interference from decorative bling rings, causing immobilizer problems. The Malibu faced a hidden short circuit in the immobilizer control module wiring due to spilled soda, blocking key programming. The episode highlights the importance of understanding immobilizer systems, diagnostic tools, and the unexpected vehicle faults that complicate key programming.
Topics:
key programming challenges
immobilizer system diagnostics
toyota camry key issues
chevy malibu immobilizer fault
ignition key switch problems
diagnostic tool usage
vehicle wiring faults
aftermarket vs oem keys
lint bus communication
key programming troubleshooting
Round 2 of why won't this F@%$'n key program?! I did an episode a year ago about attempts programming keys and the challenges we face doing mobile. Today I share 2 more vehicles that we dealt with recently- A 2017 Toyota Camry and a 2018 Chevrolet Malibu. Both had pre-existing issues that presented no issues to the customer, but presented major obstacles for us when attempting to program keys.
Vol 1- https://autodiagpodcast.com/2024/11/24/283-why-wont-this-f-key-program/
Website- https://autodiagpodcast.com/
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YouTube- https://www.youtube.com/@automotivediagnosticpodcas8832
Email- [email protected]
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Filter:
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Technical
Too Afraid to Ask
Car
Toyota Camry
"...ircumstances. So let's start out with 2017 Toyota Camry. This is a used car lot."
Car
Chevrolet Malibu
"... anyways, that's first car. Second car 2018 Chevy Malibu. This one was also a giant pain in the ass."
Select text to request an explanation
Welcome to the Automotive Diagnostic Podcast.
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Hey, what's going on?
Automotive World, welcome to another episode of the Automotive Diagnostic Podcast.
My name is Sean Tipping.
I'll be your host once again for this week's episode.
Thank you so much for joining me.
It's me on the show this week, and we're going to do round two of why won't this FNK program
to the car.
If you've been listening for a while, I had the first version of this almost a year
to the day, and I didn't plan that out.
I was just looking because I knew I did an episode titled why won't this FNK program.
It was November 24th, 2024, so strange.
We had a few vehicles last week that were just a huge pain in the ass to program keys
to, and we do a fair amount of key programming.
It's probably somewhere between 10 to 20% of the overall volume of what we do, so it
is a smaller portion compared to diagnostics and programming, but it also kind of is programming.
If you think about it, just keys have their own unique challenges.
Number one being the key itself, just getting the right key, and I've talked about that
plenty of times before where that can be a real challenge, even if you've been doing
it for a while, even if you've got some good trusted resources, there are just so many
options for particular vehicles, and once you get into the European world, it gets
even more challenging.
That's its own discussion, which I've covered topics before, but today we're going
to be talking about pre-existing problems on a vehicle that had nothing to do with us,
and we're not affecting the vehicle as far as the customer could tell until we tried
to program keys in, so that's the challenge here.
We're coming in, car worked before, now in one case they had one working key, in
the other case it was an all keys lost, but prior to losing those keys, the vehicle
started, it ran, there were no issues apparent to the customer.
Now, in a specific situation with both of these vehicles, they would have
recognized the problem, but again, us walking into it, and of course we're
taking the customer at their word, but hindsight, I think they were honest
saying that, yeah, there were no problems with the vehicle prior, we're
very confused because we can't add keys to this vehicle, and so now we're
like, okay, is it the keys themselves?
Is it the tooling that we're using or the software?
Is there something going on with the car, or are we just missing
something completely and we should stop doing keys?
Now, I don't think that's it, but it makes you feel that way sometimes.
So I got two cars I'm going to cover today that we recently dealt with.
Again, pre-existing problems on the car, they were broken.
It just wasn't broken in a way that presented itself as a symptom
to the customer in everyday driving with functional keys.
Again, would have been specific circumstances.
So let's start out with 2017 Toyota Camry.
This is a used car lot.
They sold this Camry to a customer less than a month ago.
They've been driving it around just fine, and then they end up
getting it towed back saying, hey, it won't start.
There's a security light on the dash, right?
The Toyota has it kind of in the center stack there,
the little immobilizer light.
And I don't know if it was the driver of the vehicle or our customer
that recognized that it was a security issue, but they did see this light on.
So we get out there and we're doing some other keys on this stop as well
for this car lot.
And right away, almost immediately,
I recognize what the problem is.
Now, you can see, obviously this customer just bought the vehicle.
And they blamed it out, meaning that there are sparkly,
bedazzled stick-on rings and other pieces that have been put onto the dashboard and
doors and center console and stuff like that.
So I'm sure you've seen these.
You can order a big old package off Amazon.
And one of those bling rings goes right around where the blade key ignition is.
So this is a turn-style blade ignition.
It does have a transponder in the remote head of the key.
And it goes into the ignition and there's a short-range transponder
that communicates with the halo.
The car recognizes that, hey, the key belongs to this vehicle.
And then it allows a start.
Well, and if you haven't seen this, you probably will eventually.
They get these bling rings, they stick them around the ignition, right?
Where you put the key in.
Well, there's metal in this bling ring and
it interferes with the communication between the key and the halo.
So we see it and we're like, okay, that's it.
Because we've seen this before.
This is a common thing.
It happens and it will disable a vehicle.
And a lot of times customers don't make that connection and understandably so.
They probably don't understand how the key actually functions or
that there's a transponder in the key at all.
Now, for reference on this Toyota Camry, the key that they had,
they only had one, was just a transponder head key.
So there was no remote built into the head of the key.
Although the car did come equipped, or
at least the option to have a remote head key.
And what I mean by that is the buttons to lock and unlock the vehicle are on
the head of the key, there's still a transponder chip in there.
But the one that they had for the car was just a transponder, no buttons.
So anyways, mobilize the lights on.
We see the bling ring, I'm like, okay, take that off.
Take it off and immediately the key goes in and starts the vehicle.
Okay, problem solved.
Now, we did order a key for this vehicle with the remote head because that's what
the customer requested.
They're like, hey, when they called us, they said, hey, we've got a security issue.
We don't know if it's the key or not.
We'd like you to come out, take a look at it.
But either way, the customer would like a key that has a remote on it.
Again, because the car has that option and it's nice to have the remote
rather than putting the blade in the door every time.
Sure, so we already ordered this key, so they're going to be paying for it
one way or another.
And so we figured, okay, we'll just cut the key and then program it in.
Should be easy and we can move on.
Not so easy.
So we get in and we cut the key and we attempt the programming and
it doesn't allow it to go through.
And I was actually there with one of my employees.
He tried several times with several different tools.
And it seemed like it would work at times.
So he could actually get this thing to start and it would stay running.
But then after you would take the key out that we were trying to learn,
you leave it sit for a little while, you try to go start it again and
it was immobilized again.
And he tried several different times, several different tools for a 17 camera.
There's lots of different tools that you can use to program a key,
to add a key, it's relatively straightforward.
Now I should note there is a separate process for the immobilizer portion
of the key and the remote portion of the key.
But again, multiple tools, Autel, Top-Down, X-Tool.
Those are our most common ones, any of those should be able to do it.
There's more out there.
All keys lost is a little different, but just for adding a key,
especially when you have a master key.
And I should note that that's an important thing on a Toyota if you're
gonna be adding keys in or programming keys is to have or to know if you have a master key.
If you don't, there's some other processes that need to be done in order to add a key.
You can usually tell this by watching the security indicator and
putting the key that you have into the ignition, turning it on.
If the immobilizer light never lights up with a functional key,
it generally is going to mean that that's a master key.
You can also go into the data pits and
see if the key that is in the ignition is a master key or a sub key.
This one is a master key, and again, you can watch the immobilizer light.
Immobilizer light is really important on this era of Toyotas and
many others for programming keys.
You kinda watch that and you can tell if the programming of the key is successful.
If it likes the key that you're putting in, if it's a master or sub key.
If you understand what the LED does for the security indicator,
you can tell a lot just from that.
So anyways, the key that we have, the functional one, the one without a remote,
that is a master key.
Meaning that we should easily be able to add another key into this in
under five minutes with a scan tool.
But we do not seem to be able to do that.
Now, I got involved because I was working on some other cars so
we shifted and I try the same tools, I get the same result.
It seems like the key programs at times, but depending on the tool you get,
you either get an error or a successful completed, but it didn't matter.
Either way, the key that we were trying to add immediately after trying to
program it, it would start and run the vehicle.
And if you left it running, it would run all day long, no problem.
But as soon as you shut it off, and you did have to give it a period of time here.
I think it was until the module fully went to sleep.
But then if you went to put it back in, it would not work.
It would be immobilized.
You could watch the immobilizer light that it would blink at you consistently as
long as that one was in there.
And in addition to that, we tried doing the remote portion just to see like,
does it like the remote for this key?
And it would react to the remote being programmed, but
none of the buttons would work.
So when I mean react, when you go through the remote programming for
this Toyota, you hear the car beep as a response.
I think it comes from under the hood or something like that.
But you hear it beep, and
that would be the normal beep that you would hear if you were locking the vehicle.
And that's a response to say, hey, I see that remote, it's programmed in, cool.
But even after you did that, and you'd hit the buttons, nothing would happen.
It wasn't reacting.
So we do a little bit of digging to make sure that we have the correct key for
the car.
And you can do this various ways.
Again, we do a lot of keys.
We have some good resources that we'll use to verify, okay,
this is the correct key.
Obviously for the remote portion, we want the FCC ID to be correct.
But again, that seems like it's programming in, even though it's not
reacting to any of the buttons once it is.
But even besides that, the immobilizer portion of the key is separate from
the remote, it's two different things.
So even if I've had it on Toyotas, even if the remote's wrong,
you can still get the immobilizer portion programmed in.
And I don't seem to be able to do this.
I use the key tool Max and I read the chip in the one that functions and
I read the chip in the one I have.
They're the exact same type of chip, which is what we're shooting for.
If they're different, okay, that might explain why this is an issue.
I don't quite understand why it will run at first, but then afterwards,
it's not.
So I'm looking a little closer at the system, looking for codes,
obviously.
I didn't see any codes besides the fact that if once it was in the state
where it is immobilized, it would set a code for, I think it was unregistered
transponder or something that, in fact, basically didn't like the key.
Hey, you're trying to start me with a key that is not programmed to me.
I'm like, that's definitely strange.
Now, something that has been very useful to me with immobilizer systems,
I mentioned it before, is if you have an Autel IM series tool,
you can go into the immobilizer side and you can do the immobilizer system
scan, and especially on something, if you're not familiar with what components
are involved with the immobilizer on a particular vehicle.
But even if you are, if you just want a really good system overview,
that immobilizer status screen is really helpful.
It'll tell you a lot.
And it breaks it down of how many keys are programmed, master key, sub key,
all that stuff on a Toyota.
Now, disclaimer for Autel, if you're going to go out and buy an IM series,
they did take away some Toyota and Ford key functions.
And there probably will be more in the future.
So be aware of that before you drop the money.
But at this time of November 2025, they're still able to add keys to Toyota's.
They're just, they can't do the all keys lost function.
But the immobilizer system scan still works, at least on the 17 camera it did.
And it broke it down.
Now, here's where this was a little bit useful to me, is after I would
program or attempt to program this key, the number there would stay at one.
It never went to two.
Even when I was running the car with the key, I was attempting to program.
I was like, well, that's, that's very strange.
So then I did a little bit more work going into the actual immobilizer module
on the diagnosis side of the tool and looking at the data
pins as I'm putting different keys in there to see what it's viewing the
key that I have in the ignition as.
Now, if I put the functional key in the ignition, I look at the data
pins and you're looking at, I think it breaks it down into master key and
then subkey, it'll say registered key when I put the original one in.
It says master key.
Now, I take that key out and I go to put the new key in just to see what it
says, and this is at a point where it wouldn't start.
But I watched the data pit and it never changes from registered key even
when I put the other one in.
And if I'm quick enough about it, I can start and run the vehicle that way, right?
So it's like it sees the first key, it holds onto that data and it will
allow me to start the car if I do it quick enough.
Now, if I wait long enough with your, the functional key out,
it eventually goes to no key.
And then if I put the new key in, it will say unregistered key.
It's like it doesn't like it.
It's something about the timing and I think, well, that's very strange.
And this is about the time that I kind of start putting the pieces
together here is I have the door open on this vehicle.
And of course, when I have the key in the ignition, it's dinging at me.
When I take the key out of the ignition, it's still dinging at me,
like I still have the key in the ignition.
And I'll be totally honest, I hear dings from cars all day long that my
brain pretty much tunes those out most of the time.
I mean, if you program vehicles, if you do it mobile, quite often you're
sitting there with the door open and there's some vehicles that are
much louder than others and I'll flip the door latch here or there.
But then I forget that the door latch is flipped and then I close the door on it.
So I try to avoid that.
Anyways, I was just kind of tuning the dinging out.
But this episode is brought to you by L1 Automotive Training and Keith Perkins.
If you're looking for education on module programming,
J2534, eProm work, key in a mobilizer, electrical diagnostics or driveability diagnostics.
Keith has a website, l1training.com, that's got over 60 hours of training videos
on all those subjects and more.
When I first started out doing mobile, I utilized Keith's videos on module
programming and J2534 in order to get my head wrapped around what I would need for
the tooling, the computers, the software setups, what kind of obstacles I would be
up against when I'm out there programming modules on cars and it was a huge
benefit to me and I continue to use the training videos that he has on his
website.
So I strongly recommend checking out l1training.com.
The link is in the show notes.
On this Toyota, if I don't have the headlights on and I take the key out of
the ignition, it should stop dinging because that's a warning that, hey, you
left your key in your ignition.
Don't lock your doors.
This never changed, meaning that at least what I'm thinking is that it's
thinking that the key is always in the ignition, that that master key never
left the ignition.
And so I find that data pit in the mobilizer module.
I see that the key in switch never changes states.
Doesn't matter if I have a key in out, doesn't matter how long I wait.
But here's the interesting thing.
I can put the master key that functions in and says registered key.
I can take it out.
Still says registered key, still says registered key and it'll hold on to it
for about 15 or 20 seconds and then it will go.
So there must be a periodic check to that key that only happens every
once in a while.
I don't know if it's a module timeout thing, but eventually it lets go.
But if you swap in the new key, which is cotton, it'll turn the ignition.
It's like, okay, yeah, I already saw a master key and it'll allow start.
Now a couple of ignition cycles or time and then you're not able to anymore.
But that's why when I was trying to program it and it seemed like it was
going, it really wasn't.
It was just using the data from the original key and I'm still starting
it. And that's why the tool would say failure to program.
And actually one of the tools that I was using, I think it was the top
done Phoenix smart gave me a different message when I was attempting
to program and it would say this key is already registered to the vehicle.
And I was like, okay, well, it must see that this one's programmed.
And it's just like, okay, it's already programmed.
But I did mention the number of program keys never change from one.
And what it was saying is like, Hey, you're trying to register
the already registered master key.
It's already programmed.
And so it was never seeing the new key that I was trying to program
into it because it never saw the key come out.
And if you're familiar with Toyota programming, the steps on this are
very clear that you have to turn the ignition off and take the key out
in order to advance in the programming sequence.
And this never happened.
So the reason is, is that key in switch.
Now I've dealt with this before on vehicles.
I had a Hyundai that was trying to program in a remote and the remote
programming actually happens when the key is out of the ignition.
Well, that switch, uh, because this was a stolen vehicle and they
kind of hacked apart the steering column.
They didn't install the switch correctly.
And so it always thought the key was in the ignition.
So it would not let you program the remote in.
So we had to fix that switch in order to program in the remote.
It was the same thing on this Toyota.
So at this point, I ended up taking apart the shell on the column.
And I looked in there and I see that there are two wires that are
twisted together and there's no key in switch.
It's gone.
It's not there.
And so somebody at some point took it out.
I don't know why, maybe damage, whatever, but I separate those
wires and the ding stops.
And so then I was able to just manually touch and release those
wires as I was moving keys in and out programs, new key, it's fine.
Now I mentioned the remote portion.
As soon as I separate those wires, the buttons on the key respond as well.
That car is designed so that if the key is in the ignition, it's not
going to respond to the buttons that you're pressing on the remote.
So all that made sense at that point.
And I summarized that in 20 minutes for you, that was closer to
an hour and a half that we spent on that car trying to add a key into it.
So in real world, we dumped quite a bit of time to figure that out.
Now, um, it is information that I really want to take with me and
be conscious of because I didn't think of the, to listen for the
dinging on that door to look at that data pit, but boy, it's
something that's going to be part of our process now is to make
sure that that like key in switch actually functions on a car before
we attempt to do any sort of programming.
Cause obviously that's an important input in the key process.
Now the customer never noticed an issue bling ring aside.
That was the first issue that was resolved on this one.
But prior to that, the car start and ran fine because they just
had a blade key with no buttons.
So they didn't know the remote functions weren't going to work.
And the car start and ran with the key that they had, they
just wouldn't have been able to add another key like we were
trying to do, right?
That problem, I mean, I guess it would, it would
ding at you anytime the door is open, even if the key's out.
Again, maybe you just don't notice that.
You just think all the car dings at me when the door is open.
But otherwise you may not never notice that there's a problem
with it as a driver of the car.
If the keys are already programmed in, but when you go
to program them, now we're presented with this issue that
we have to get past.
So anyways, that's first car.
Second car 2018 Chevy Malibu.
This one was also a giant pain in the ass.
Now this one was an all keys lost lost other keys car
function prior to that, no other history on the vehicle.
Like they've owned the vehicle.
They were they were driving it keys worked all functions.
And again, we're taking them at their word.
But afterwards, I believe that it was the truth.
That's what was going on with this one.
It's a push button start system.
There's a key slot in the center console.
There's a little pocket at the back of the cubby there
in the center console and this GM programming.
Very simple.
We've done tons and tons and tons of these.
The deletion picking the doors the hardest part of getting
the cuts out of the door doing the remote, you know, 12 minutes
you're in and out easy peasy.
Well, this one was not so easy peasy.
Set my employee out to attempt it first.
Wasn't able to do it wasn't able to do it.
OK, well, let me run out there.
I'll see what I can do.
Some different various tools.
I spend a bunch of time on this thing can't get this to go.
It is blocking me when I attempt to program these keys
and I even tried with TLC, which actually works pretty well
for key programming.
You don't need VSP or anything like that for general motors.
And I've had a few of them where I don't know, the
auto or the aftermarket tools just, you know, give me
hassle in trying to do an all keys lost.
But GM's program will work just fine.
But TLC did not work with this application either.
Still fought me and it was at the point where I was trying
to register the keys when they were supposed to be placed
into that pocket and you go through a learn procedure
where it cycles the ignition on and off and you're
pressing the button.
But basically at the point where it was supposed to
learn the key in that short range transponder pocket,
it would just air out so the key can't be learned.
OK, so back to the same thing.
Are these the correct keys?
Do our research, make sure.
Yes, these are definitely the correct keys.
I even tried making an auto universal smart key just as
like, let's try this because I've had auto universals bail me
out of some weird key issues before wouldn't let me still
failed. Same thing.
OK, so again, that that question mark of is my key
correct is always on my mind, especially with
aftermarket keys, right, because there are cars
out there where we've just had to pony up the money
and get the OEM key.
The aftermarkets won't work.
That's again, its own pain in the ass.
But from everything we can see here, these are the
correct keys for this vehicle, and I've not had this
type of problem using the keys that we get from our
supplier on General Motors vehicles.
So I'm going to do a little bit of digging on this
one just to see like what else is going on with the
vehicle. And my assumption was there was more
going on, and we just weren't being told the
truth. Again, hindsight, I don't think that's
the case.
I mean, there is something broken on this vehicle,
but again, same thing.
Customer probably had no clue that this thing was
broken, and it would have been a certain
circumstance for them to be able to recognize a
problem. No bling rings on this one, but it's a
push button start anyway, so you could put one on
there. You probably be fine.
Anyways, no codes in the vehicle.
Besides the fact that we were able to race
the keys, I think the BCM was in learn
mode. That was the code that we did have in
there, but nothing else pointing to an issue
on the car.
So I'm going through the process and I'm kind of
watching. And one of the things that I did
was I use my key tool, Max, and you can use
other tools for this as well. There's several
different tools. You can buy a little ring that
has an LED on it. You can use the Otel KM
100. There's a handful of other tools that
will detect an ignition coil signal.
So this could be for a blade style key or
it could be for the pocket for a smart
key. And you hold whatever tool you're
using up to this pocket, where the key is
in close proximity, and you attempt to
activate it, whatever that is, press the
start button, try to learn the key, turn
the ignition. That should trigger the
vehicle to make that connection with the
key with the short range transponder there
and the key ring or the halo, whatever
you want to call it. This one, it was
not OK, so I could sit there and I could
push the start button. I had no activity
there. I could attempt to learn the keys
and when it got to the point where it's
supposed to be taking the information
from that transponder, it's not doing
anything. OK, so I took off the back of
the center console so that I could
access this component and I see the
little ring that is on the backside of
that pocket, right? It's plastic, so you
can't see it from within the center
console, but on the backside you can
see there's a little ring that snapped
on there and it goes to a tiny
control module that's only a couple
inches that's bolted to the back of that
center console assembly. It's got two
wires going to the coil itself and then
it has a three-wire plug which goes to
the body control module. Now this little
module is called the immobilizer control
module on this vehicle and really its
only purpose is to run that key ring,
the halo, and get information from the
key in that pocket and then send
that information to the body control
module on a lint bus. So it's got three
wires, power, ground, and lint. Very, very
simple system, right? Now it does not
seem to be doing anything. Again, when
I press the button on the dash, when I
try to program the keys, nothing's
happening, nothing's happening, I don't
see anything. So let's check the circuits
to it. So I have ground, awesome,
that's what I'm looking for. I have a
lint bus which stays high most of the
time but I can get it to pull down low
like if I'm cycling the ignition or
pressing the button I see activity on
this lint bus and it does seem to be
coming from the BCM that it's there's
data being transmitted on there. It's a
high voltage gets pulled down low when
communication is happening and it is
only between this immobilizer control
module and the BCM. The wiring diagram
is very simple, just three circuits
right to the BCM. I shouldn't say right
to the BCM, there's connectors in
between but it goes to the BCM, it's not
connected to any other modules. Okay,
lint bus seems to be there. There is a
power wire as well. I have no voltage on
this. Okay, so maybe this is my problem.
Why don't I have voltage on this wire?
Obviously control module needs to be
powered up, whatever, you know to
operate and I have nothing there.
Okay, so I go to the body control
module which is really simple in this
one. You pull the carpet down on the
passenger side of the center console
area and the BCM is right there. This is
the third connector over from the left
and is the first three pins on the
connector. So really simple to find. All
three that go to this immobilizer control
module are next to each other on the
connector on the BCM. Again, power
ground and lint. And on the factory
diagram it shows you that the BCM
supplies 12 volts to this immobilizer
control module. It shows you right there
clear, plain and simple. Look the diagram
up for yourself. If you look up the
symbol on there it is straight 12 volts
from the BCM to this immobilizer control
module. Okay, I don't have that. There's
no voltage there. Okay, well here, that's
my problem. And I tried hitting the
button and all that stuff and no 12
volts on this wire. I'm like, okay,
well this is what's going on. So why
is the BCM not providing 12 volts on
the circuit? Okay, so obviously check all
the powers and grounds of the BCM. Step
one. Really easy to do in this one
actually. Just go down the row and you
can find all the powers and grounds.
They're all there. They all light a
headlight bulb. Pull the proper amount
of amperage. Okay, that's cool. Let's
unplug this connector from the BCM and
do a couple of things. Number one,
I want to see if this BCM can
provide 12 volts with this circuit
disconnected. Maybe there's something
on the circuit that is pulling it down
to ground. And when it's unplugged, I
check that circuit for a connection to
ground and I don't have it. It's OL to
ground. Okay, that's what we want to
see. And I also check the continuity
from that circuit to the immobilizer
module. Easy to do. I've got
continuity from end to end. That's what
I want to see on that wire. Again,
no 12 volts out of it. I don't have
a pathway to ground on that module or
on that circuit. And so I test the
circuit right out of the BCM. So I only
have one connector unplugged and you
do want to be careful here if you're
doing something like this because what
else is on that connector. But I just
wanted to see, am I getting
anything on that circuit with this
disconnected? And what I saw on there
was two volts when I would check that
circuit. I'm going right to the pin
on the BCM with this connector
unplugged. I'm only getting two volts
there. I'm like, okay, well, that's
an issue. And then if I plug the
connector in, it drops down to zero.
And I look at the diagram and I see
again, okay, 12 volts, you can look
at the service information for the
description of this module. And it says
it provides 12 volts to this circuit.
All data says the immobilizer module
also receives B plus and ground from
the BCM. That's straight from the
system description and operation. So
again, everything I'm seeing there,
I'm like, okay, well, this seems
like something's going on with this BCM.
It's not providing 12 volts on this
circuit. Now, the one thing I could
have done is tried to jump 12 volts
to this to see if I could learn the
keys in. I didn't do that at this
point. I'm like, okay, well, something's
up with this BCM. Let's get a BCM for
it. We had already spent a lot more
time on this car than I was looking
for. So it was like, let's get a
BCM for it and we'll move on with
our lives. So we get the BCM, new
BCM from GM, put it in there, and we
get the exact same thing. Can't
program the keys in. You can do all the
other BCM programming, but we are
unable to add the keys in. It fails at
the same point. It does not activate
the coil in the same way. And when we
check the circuit, it ends up being
the same thing. And again, I unplug
it. I get two volts on that circuit
and when plugged in it goes down to
zero and I'm like, oh, you kidding
me. Like, what's going on here? So
this is where I messed up here.
I did not do a thorough enough
check. I didn't think about this enough.
There was another check and
there's something about the circuit
that I didn't know. And now I do and
now you will. You can find this in
service information, but I don't know
how I would have if I didn't know
what I was looking for. But anyways,
here's the deal about this circuit.
And it says, the only place I found
this was in a DTC description,
basically the flowchart for
diagnosing the security data circuit.
So that's the circuit between the BCM
and this mobilizer control module.
And on number four, where it's having
you check for voltage on the power
wire, it says, note in some instances
the K9 body control module may only
apply voltage for three seconds
immediately after the ignition is
turned on. It may be necessary to
monitor the multi-meter while
turning the ignition on to observe the
voltage.
Okay, now number one, I couldn't turn
the ignition on normally with this one
because we didn't make keys programmed.
I could force it with the programming
mode, but I didn't do that while I was
doing my checks. And so apparently
two volts on this circuit in a
rested state is completely normal.
It will power up the circuit again
key on and I think what it will do and
what the other thing it will do is if
you're actually up there pressing the
button and it's triggering
the module to look for a key, it will
power up that mobilizer module.
At least that's the case on this 18
malibu because it doesn't send power
back to this thing until it needs to
operate it and check for a key.
Otherwise, it is just a two volt
bias, if you will. I don't know the
purpose of the two volts there, but
that's all that's there and that's
normal and that's how this one operates.
Now, going back to it being plugged in,
it drops down to zero. I'm like that's
interesting that that you know drops
down to zero after completing this
diagnosis. That should be at
two volts as well. It shouldn't get
pulled down to zero. What it ended up
being and what I did not check on my
first trip is that wire was
shorted to ground, but it was only
shorted to ground when the
connector was plugged into the BCM.
If you remember before I had unplugged
the connector, I had tested for a
short to ground. It was not there, but
plugged in it was and here's why.
The short to ground was actually on the
ground wire for the immobilizer control
module, right? So the BCM supplies a
ground to the immobilizer control
module through another pin that's
right next to it and that wire was
shorted to the power wire, okay.
Now, where this was was on a
connector under the center console
that a bunch of pop had been spilled on
at some point and after I looked at the
diagram like okay let me access this
connector. I pull off the center console
plastic. I see this connector it's all
full of pop, pull it apart, clean it up.
Now that short between the power and
the ground wire go away,
but again I never checked for that
the first time I was looking at it.
That's my, I missed that one for sure
100%, but with the second look I was
like okay after I clean that up
guess what that wire stays at two volts
until again you go to program keys, hit
the button, get that coil to activate
somehow and then the BCM will power up
the circuit and it will trigger the
coil to read the key and the keys went
right through. So on this one
again the customer probably had spilled
pop it looked like quite a while ago
on the center console and into this
connector and maybe other circuits
would have been affected.
Again I didn't have any codes
that I saw that were relevant,
but this wouldn't have been a problem to
them unless the key battery was dead
and they tried to put it in the pocket.
It wouldn't have worked, they wouldn't
have been able to start the car that way
but before they lost their keys
that wasn't an issue, their keys were
programmed, they worked in a proximity
mode, it was using low frequency
antennas and everything was good.
But when we went to do the all keys lost
that coil portion didn't work
because that power and ground to
the immobilizer control module
shorted together with pop
in I think it was
connector 300 right underneath that
center console there so that's a common
place if people are spilling stuff
it's going to get soaked with
whatever they're spilling on it.
So anyways those were two
rather frustrating vehicles
obviously on the Malbu made a bad
call before we got it figured out
but I thought it would be worthwhile
sharing and if you're doing keys
at all I'm sure you understand how much
of a pain it can be sometimes if
you're looking on getting into keys
just understand when keys go smooth
it's really good it's like printing
money but when keys do not go smooth man
it can be real real pain because
there's a lot of variables including
broken things on the car that weren't
even apparent to the customer prior to
you trying to add a key.
So hopefully you found something
interesting learn something out of
that but other than that like thank
everybody for listening always
appreciate it let's get out there start
fixing the world one car at a time
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