337: BMW X1 Parasitic Draw Diagnosis Throws Me A Curveball

Welcome to the Automotive Diagnostic Podcast.

We're going to explore ways to sharpen our diagnostic skills, find learning resources, and hear from

experts in the automotive field.

This show is brought to you by Automotive Seminars.

If you're looking to stay up on the cutting edge diagnostic strategies and techniques,

this is the place.

You've got live four-hour seminars that are put online that you can join in, ask questions,

interact with the instructors.

With some of the best of the best, they've got Keith Perkins and John Thornton putting

on classes like Network Diagnostics, Mechanical Engine Testing, Advanced Electrical Testing,

and GDI Diagnostics, and a ton more.

Once you purchase one of these training seminars, you can access this at any time that you want

through your account at AutomotiveSeminars.com.

You can re-watch the training a year, two years later, which makes this training even

more valuable, so I highly recommend you check this out.

The link is in the show notes.

Hey, what's going on, Automotive World, welcome to another episode of the Automotive

Diagnostic Podcast.

My name is Sean Tipping, and I'll be your host once again for this week's episode.

Thank you so much for joining me.

This week on the show, I'm going to share another case study with you from out

there doing mobile diagnostics and, of course, it's going to be another parasitic draw.

Yes, I do a lot of these.

I find them to be the most interesting and sometimes the most challenging diagnostics

to perform.

I mean, if I came on here and I talked about a single cylinder misfire or that time that

I smoked the intake and found an intake leak, that's not as exciting, at least not

to me, and I don't believe to you that that would provide a ton of value for the most part.

But these parasitic draw ones, not only, again, are they challenging, I think they're interesting,

and I learned the most, especially when I deal with a vehicle or vehicle platform

or even sometimes just a problem that I didn't know prior to going in to that situation.

This vehicle is no exception.

This is a 2017 BMW X1 that's got a pretty significant parasitic draw.

This will kill the battery overnight easily, and it's been very consistent for the shop.

They looked at it a little bit, but they quickly realized this is outside of our realm.

We don't do that much parasitic draw diagnosis at all.

And then being a later model BMW just wasn't something that they wanted to dive into.

So they call us to take a look at it.

And of course, I teach a class.

I've talked about parasitic draws.

I just had an episode recently that's saying that parasitic draws on modern vehicles

are really just network problems in that when you observe there's a certain level

of current draw on the battery or how it's acting in certain situations,

you can move directly to the network and skip some of the other procedures

in a normal process that you would do for a parasitic draw.

And that's actually kind of why I wanted to talk about this one,

because that's what I did on this one, but it ended up being more challenging than I thought.

And I didn't get to the solution in the way that I thought that I was going to.

And I spent a lot of time on this one.

This one burned up a decent portion of the day because I was kind of lost for a little while.

So why not talk about it?

Of course, if I'm going to put something out there on the podcast,

sharing information with you, of course, I want to bring up when,

hey, that thing that I said, it didn't work perfectly here.

And I mean, as technicians, I think we all know that as we can have a skill set,

we can go to a class, we can learn something, even just a tool.

We can have a tool like, man, this tool is great for X, Y, and Z.

But every once in a while, you run into a situation where that tool or that procedure

or that piece of knowledge doesn't quite apply the same way.

It's real life.

There's nuance.

There's going to be curve balls that come at you.

This is one of them.

So I want to talk about it.

And again, I learned quite a bit.

I think next time I get one of these, I will be able to handle it better.

But you might be somebody who does a ton of parasitic draw stuff on Europeans

or specifically BMWs.

And you might have a simpler way to get there.

I'll talk about that at the end.

Little hindsight and research after the fact.

I may have been able to get to this solution quicker, unknown until I try again.

But that's why I try to take the time after diagnosis to learn.

See, could I have done that better?

Because I definitely was not efficient this first time around with it.

So anyways, let me set up the vehicle again, parasitic draw 2017 BMW X1.

What I ended up finding was this was all the time.

I didn't have to wait for it to act up.

And you didn't have to wait for it to go to sleep because it never fully did, right?

There's some vehicles where we have to wait a certain period of time so

that the initial amperage draw off of the battery after a key off will time

out so that we can see the consistent draw that's on the battery, right?

And whatever that time frame is, some are going to be very quick.

Some are going to be very long.

Depends on the vehicle, depends on their normal power down process.

And it depends on the level of draw, right?

If it is a six amp draw, you're not going to have to wait very long.

You can start diagnosing that right away.

That's, again, when the key is off.

It should drop down to, this is real blanket statement, but

it's pretty true on most of the stuff that I observe.

It should drop down below two amps on just about every vehicle

within a few minutes, less than five minutes.

Now I'm sure there's an exception out there.

There's lots of different vehicle platforms and

lots of different applications out there.

But if I see it hanging above that point for longer than five minutes,

I'm going to go after that, right?

I'm going to look at that vehicle and say, okay, I need to find this draw.

And I'll keep an eye on it while I'm doing that.

And if it eventually does drop back down, okay,

I'll reassess, but vehicles are going to drop down below that two to three amp range

pretty quickly after you shut the key off, close the doors, the hoods, right?

Put it into its proper sleep state, okay?

Now, this vehicle was bouncing between four,

it's like four and a half amps and six amps.

And you could watch it.

And again, I'm just using my amp clamp, negative battery cable.

And I'm watching this thing.

And so it would be up at six amps for a while.

It would drop down to about four and a half, then it would come up to six.

And it took me a little while to see the pattern, but

there was a very specific pattern to this.

It would be 20 seconds on, and I use my phone to time this.

It would be 20 seconds on for six amps.

And then it would be five seconds off where it was still four and

a half amps, and then back up to six amps.

And we'd do this indefinitely until the battery was drained.

Put a charger on there because, of course, that's gonna drain a battery

pretty quickly even just sitting there doing the diagnostic at six amps.

So, but that's a pretty heavy draw, right?

Now, that being said, like I mentioned before,

if you have a larger amperage draw on a modern vehicle,

one of the things you should consider is the network is awake.

Now, I had some very obvious clues that a network or

networks were awake on this vehicle.

I should back up.

I did a pre-scan on this thing, and there was lots of voltage codes

from the battery being dead.

But I did not have any codes that pointed to anything that

looked like it was out of place, or that there wasn't any smoking

gun within the trouble codes that pointed to, hey,

this is something I really need to check out.

Just a lot of codes indicating that, hey,

the battery voltage was below the acceptable threshold.

And understandably slow, if this thing is pulling six amps out

of battery most of the time.

So anyways, pre-scan is important, especially on something

like this and clue you into where you need to go.

Don't forget to unplug your VCI from the DLC when you're

doing this because that can be a draw.

Anyways, the draw was about six amps on this thing bouncing

back and forth.

And I had some clues that network or networks were awake.

When you looked inside of the vehicle,

and this is true for a lot of BMWs that have a actual shift

lever, they'll have a little indicator that

indicates the gear.

So there'll be a little green LED next to the P, which

is Park, and this was illuminated constantly.

I also noticed that the backlight for the hazard switch

was illuminated, and one of the LEDs on the driver's

window switch was also illuminated.

And those stayed on indefinitely.

And that's a very good clue that there is some sort of body

can or K can, as they call it, that's still awake and talking,

and that there's modules that are just waiting to go to sleep.

So that kind of was a visual confirmation to me that, hey,

I've got networks that are awake.

And so if you go back a few episodes,

I had the discussion about parasitic draws.

We should really just consider, let's

start looking to see if the networks are awake.

Because if the network or networks are awake,

doing the amperage draw of individual fuses or voltage

drop across fuses isn't going to be super effective,

because you're going to find a number of fuses withdraw

because there are a number of modules

that are awake because the networks are not going to sleep.

So it's going to be an inefficient process

to track down which module it is based off of the fuse.

Yes, you could say these six modules are awake,

but then you still have to disable them somehow.

So my approach on other vehicles is

let's separate the network down and then figure out

which component is keeping the network awake.

So anyways, at this point,

I need to understand the network structure of this vehicle

and figure out how I'm going to approach this

to figure out, is there multiple networks awake?

And then if so, how do I break that down

into different sections?

So how do I identify which network is the one that's talking

and then how do I break it down into different sections?

And this is where this one went a little sideways for me.

I mean, I did understand the structure

and basically the body domain controller BDC

in the right front kick panel is the gateway

for the vehicle, meaning that if you plug

the scan tool into the DLC,

it's going to that body domain controller

and then it's going to connect your scan tool

to the various networks through the module.

It is the gateway.

So you're not physically hardwired to any of the networks

at the DLC, but if you go to the body domain controller,

you can access all of the networks.

And there was four different ones on this vehicle, I think.

And there seemed to be one main connector

that had majority of the network wires going to it.

It wasn't all of them, but it was most of them.

It was connector eight at the BDC.

I was like, well, this is a great place.

I will unplug this connector

and then I'll monitor the networks for activity.

Unfortunately, that did not work out

the way that I had planned.

And there's a little bit of hindsight here of,

okay, well, this makes sense.

I spent too much time at this module

and at this connector, trying to monitor the networks

and then disconnect this connector from the module

and see who was still talking after I disconnected it.

The problem ended up being

was when I disconnected this large connector.

And this is true of any time you're doing

a network separation or a module diagnostic

where you are unplugging a big connector

that has a ton of pins on it.

There was almost 40 pins on this particular connector,

which is true of a lot of connectors on modules.

They're gonna have a lot of pins.

You're gonna have a lot of circuits.

My goal is just to remove network wires from this module,

not everything else that's on the connector.

But the problem is, is unless you de-pin it

or unless you cut wires,

you are gonna be removing everything from that module.

Now, when I was doing this,

I was disabling a portion of the module

that played a role in why things were staying awake.

So basically when I would unplug this connector,

our draw would go away.

And when I would plug the connector back in,

the draw would no longer be there

until I cycled the key on and off again.

And that was an important clue,

but I didn't quite fully understand it.

But I realized in the moment

that I couldn't use this as an effective strategy

because after I unplugged this connector,

it seemed like whatever was happening went away.

Now, must have something to do with it,

but I didn't quite understand what, right?

Is disabling the BDC in the way that I did the key

or is taking those network wires away from it,

disabling it, I wasn't sure.

But I decided instead of unplugging at that connector,

I was gonna go after individual networks

and try to separate them at different points

and see if I could trigger it that way.

Now, I will say I monitored,

I think three different networks

that had activity on them while this thing was drawing

and all three of those did go to this connector.

Now, again, you could deepen, you could cut wires.

I like to try to find connectors or points

to where I can break the system

without having to cause any damage.

I mean, number one, we don't wanna modify

the communication wires unless we have to,

but also for my standpoint as a mobile technician,

the more that I take apart is the more that I have

to put back together before I wrap up the job,

which I would prefer not to do.

So I try to do things where I can just unplug

and plug back in rather than actually have

to do a wiring repair after I'm done with the diagnostic.

I will, if I have to, away my, you know,

what the value of that test is gonna be,

but I took a look at the diagram

and I saw that this vehicle uses

some terminating resistor connectors

that are towards the rear of the vehicle

in the luggage compartment.

And if you look at how these are set up on the diagram,

there are multiple legs of the network

that go into these connectors.

They're like 26 pin connectors.

The resistor is within this little plastic housing.

It's almost like a star connector on a Chrysler

if you wanna think of it that way.

And I was like, well, this would be a great place

to break up the network.

Finding them, it's a little tough.

You gotta pull a panel in the back

and there's three of them back there.

And one of the networks that had activity on them

had its own terminating resistor back there.

This was a violet white K-can four.

It's a body can for the vehicle.

Had activity on it.

And I'm like, okay, I'm gonna start with this one.

Now, the problem was when I got to this component,

which again, I had to pull a panel to get to it.

The diagram did not match what I found

at the actual terminating resistor in the connector.

There was only two different network legs

that went into this.

Where on the diagram it shows many more than that.

But if you pay close attention to the diagram,

the vehicle options change what actually intersects

at that terminating resistor.

And so this ended up being a waste of time too.

I did unplug it and it didn't shut anything down.

I still had activity on the network,

but I wasn't sure exactly how the wiring

was structured in this one.

I had an idea, but it was tough to say

based off of the diagrams.

Hey, have you ever been faced with the challenge

of sourcing, installing and programming

a used control module in a vehicle?

I know a lot of us have.

It seems to be happening more and more often today

with the volume of control modules on vehicles,

the cost of some new ones,

or even the availability of new control modules

in some cases used may be the only option.

So what do you do here?

I strongly recommend checking out SJ Auto Solutions

and Tommy Oliva.

Tommy offers a cloning service for used control modules

to make these things plug and play

for the vehicle that you're working on.

In a lot of cases, he is also able

to source the control modules if you're unable

to locate one for the vehicle that you're working on.

But once you get connected with Tommy,

he's gonna offer fantastic support from start to finish

to make sure that that control module

is gonna work in your application.

He's also got tech support that he offers

through his website along with some free resources

there as well on information

about used control module programming.

So make sure to check out SJ Auto Solutions.

I can't recommend that enough.

And so I looked at a few other areas

where maybe I could break this down,

but the problem was I wasn't even entirely sure

that this was the network for sure

that was keeping everything awake.

I just knew that it was awake

and I saw activity on other networks.

I knew those were awake.

So I wasn't really making any progress

and I didn't feel like I had a real direct path

to figuring this out, taking the approach that I was.

Like I mentioned on a couple episodes ago,

this is a process that I've used on other vehicles

that generally is pretty effective.

It just wasn't working out on this vehicle

in the way that it was set up.

And again, there's some hindsight

as to why this was,

but I decided to kind of take a step back,

look at this a different way

and maybe just take a different approach

to trying to figure this out.

Now, I was kind of watching the draw the whole time

just to make sure that it was staying constant.

The only time I got it to go away

is when I had unplugged that BDC module

or the one connector at it.

But it was once you cycle the key on and then back off,

it would continually do this four amp to six amp draw.

And what it looked like is a module,

especially given the specific frequency of the time,

20 seconds on, five seconds off,

and it was always that amount,

that to me is like, it's gotta be a module

for it to be that specific rhythm.

So I know I'm looking for a module,

I just have to figure out which one.

And also it makes sense why it's not fully going

to sleep because something seems to be maybe power cycling

where it's like turning on drawing amperage,

shutting off for a brief period of time.

And that four and a half amps is probably the amperage

that you would see briefly after you shut off the key,

but it should go away relatively quickly

and drop down to under an amp within a couple of minutes,

but it never gets that chance

because something again seems to be power cycling on.

So I know that I need to stick on the idea of a module,

I just need to figure out how to get a little closer

and narrow this thing down for me.

So I did try something with the scan tool at this point

because I have dealt with BMWs before

where you could do a forced power down

through whichever module is in control of that.

Older ones, it was maybe the CAS module.

This one it is that BDC

where you can actually go in with a scan tool

and you can force a shutdown of the system.

Now, here's the interesting thing.

When I did that with a scan tool,

it did shut everything down.

You can see the little light go off on the park symbol.

That was kind of my visual indicator.

The network traffic would drop off

and the draw on the battery would actually go away.

It went to four, it hung there for maybe 30 seconds

and then it dropped down to an amp.

And then after approximately 10 minutes or so,

it would drop down to like 60 milliamps

right where you wanted it to be.

So where I'm going with this is forcing the vehicle

to power down through the BDC was possible

and whatever was cycling on and off the module

stopped doing so.

So the question is why?

What is different about me commanding it to happen

where it's not happening normally?

Now I'll pause here and mention something

and this is hindsight.

This is research after the fact.

There is a function through ISTA

and maybe you can do it with aftermarket tooling,

I'm not sure, but this is new to me

because I just haven't done enough parasitic draws

on BMW vehicles where you can run a function

called energy diagnostics.

Now it's possible and again, I haven't used it

so I can't say maybe you have,

maybe you can add some details onto how this has been useful

in a situation like this,

but it potentially has the ability to tell you

at the very least that the battery is drawing

because the vehicle never entered a sleep state

and it might give you a most likely cause.

And that's the most I can say about it.

I tried looking for a video of someone doing it online,

couldn't find it, there's text about it,

there's a BMW TSP about it

and it definitely looks like it's something

that I should have run and maybe you BMW guys out there

can tell me like, yeah, you should have done that first.

I'm definitely gonna try it next time

after reading about it,

but that's energy diagnostics within at least ISTA

and maybe available in aftermarket tooling.

So that might have been the thing to do here

while I'm on the scan tool side of things.

But anyways, you can run that force power down

that's a special function.

I just did it with the top down

and it turned everything off.

Now again, at that point,

you'd have to remove the scan tool or exit the function,

cycle the key, and then it's right back to where it was.

So again, it powers down when I tell it to power down,

but if I don't, then it just keeps doing this

power cycling thing indefinitely until the battery's dead.

So again, a module, there's networks awake.

The BDC definitely has a role in it,

but I still didn't have a specific direction

or even a way to narrow down pieces of the system.

So instead of doing that, I decided I'm gonna back up here

because I was feeling like, man,

I'm not really getting anywhere.

I'm not moving into a funnel of any sort.

I don't know a specific network that I need to go after.

They all seem to have traffic

and it's not like they're waking up,

they're all staying awake.

So I can't time out which one is the first one to talk.

But what I decided to do was go back to what I was

not doing in the beginning

and use voltage drop across fuses.

And my goal here is, okay, well,

let me figure out which modules are actually awake.

And maybe, here's my thought,

maybe I can figure out which module

is getting that huge like amp and a half jump

as this thing power cycles.

That was my goal here is like,

maybe I can tell which module is the one

that is waking up based on the jump in amperage.

Cause again, I could time it.

It's 20 seconds on, five seconds off.

So really I'm just looking at fuses

that have voltage drop right now

with the key off, of course.

And then I do it for 25 seconds

looking at the voltage drop.

And that should change, right?

If you jump up an amp and a half in current,

you're gonna see a voltage drop change across that fuse.

So I was like, I'm gonna look at it this way.

I'm gonna change my approach.

And it takes a little bit more time,

but this is the approach that actually worked for me here

was I was going through the fuses

and I was actually in the glove box.

There's a power distribution box

at the back of the glove box.

And I was going through the fuse

and it took me, I don't know,

probably 10 fuses until I found it.

And it was a 20 amp fuse, fuse 61.

And it was going with that 22nd on, five second off pattern.

And it was like 1.3 amps

if you do the calculation with the voltage drop.

Okay, so I'm like, hey, this very well might be it.

So what do I do?

I remove the fuse, okay?

And once you have found the fuse

that you think is the draw,

of course, pull it out, right?

And here's the other thing

and I've talked about this in my classes

for parasitic draws.

If the network's awake,

you don't have to worry about waking up the network.

So go ahead, disable stuff.

It's not as big of a deal.

If you're concerned about waking up the network,

that's a different story.

But in this case, yeah,

I'm just gonna pull this fuse out.

I do within a few minutes,

the vehicle's fully asleep, okay?

That power cycling goes away.

It goes down to like four, four and a half amps,

but within a minute or so,

it's down to an amp

and within a few minutes after that,

it's fully asleep.

Just like if I had caused it to power down

with the scan toward the BDC, okay?

So I found it now.

What's on this circuit?

There's only one thing on this circuit.

It is the head unit or the H-U-H.

It's the radio essentially.

It's a silver box behind the dash on this one.

And that's the only thing this fuse powers.

And so I can go to that module

and make sure that there's no inputs

that are keeping it awake.

There wasn't.

I looked for TSBs to see if there's like an update

to fix something like this.

Didn't find anything.

And I talked to the shop about the cost

of doing an update on this car.

It's an F chassis,

and so we're gonna have to update the whole car

and it might not fix anything.

And then if it doesn't fix anything,

then we're gonna have to do it again

anyways after you replace it.

So they're like, yeah,

we'll just tell them to get a new one.

It didn't strike me as something

that an update would fix anyways

with the way that it was power cycling,

like an amp and a half of current

continually in the off position.

I mean, who knows?

Tell me if I'm wrong,

if an update might have fixed it,

but that's another two hour process

just to try on an F chassis car like that

using its done.

So they're just going to get a new module

and put it in.

But anyways,

looking at this in hindsight,

it made a little bit more sense

the way that things happened.

Now,

when I remove that fuse,

I remove power to the module,

but the important part to understand there

is where this Fuse 61 gets power from.

It gets it from the 30B relay,

which is also in that power distribution box,

but that is controlled by the BDC, right?

So this is a relay

that powers up a bunch of stuff in the car.

It's not just the head unit,

but it is turned on by the BDC.

So two different things that happened

while I was working on this.

When I had unplugged that one connector,

I had disabled part of that BDC

and it turned off that 30B relay

so that when I plugged it back in,

the radio or the head unit no longer had power, right?

When I forced everything to sleep using the scan tool,

the BDC turned off that 30B relay,

the head unit no longer had power.

I had to key it up in order for it to have power again,

but once it did receive power,

once the 30B relay was turned on,

which is supposed to happen with a key on scenario,

then once you shut the key off,

that BDC has to see certain things happen

in order for it to shut it off.

Now, according to some stuff that I read,

it's supposed to eventually shut it off

if it sees that there's a problem.

Didn't seem to happen in this case,

and maybe it had to do with the way

that this module was power cycling.

I'm not sure, but it never did shut it off

unless you forced that to happen with a scan tool

or you unplugged that connector

or you removed the fuse to the module

that was power cycling, which was the head unit, okay?

So again, a little bit of hindsight there,

but it made more sense with what is happening.

So in the future, how would I approach something like this?

Well, maybe I'll look and see, oh, hey, 30B relay is on.

What happens if I remove that relay?

Does that put the car to sleep?

Okay, well, it's something off of that 30B relay

that is staying awake, right?

So then I can narrow it down to that set of modules

and approach it a little bit differently.

But there's a cycle there, right?

It's not just in a lot of vehicles

that I've dealt with, with networks that stay awake,

a module has constant power all the time.

It has, especially body modules,

they have the ability to wake up

and start talking at any time.

This one doesn't necessarily have that

because it's reliant on its only power source,

which is from that 30B relay,

which is controlled by the BDC,

but because of how it was acting,

it was never allowing it to actually turn that relay off

and go into the sleep state.

So really interesting, again,

this one took me way too long,

but I learned a lot about the system.

And again, I'm gonna try the energy diagnosis

the next time that I have one of these

and see what if that,

would that have gotten me to it sooner?

Would it have just told me

that it's never entering the sleep state?

Okay, I already knew that,

or would it dial me into the module quicker?

Maybe, if not, I can still use this,

you know, the 30B relay

or maybe there's another relay like that

and disable that to see what does that do

about my situation?

Does it change anything?

Are there still things talking on the network?

And then that's gonna be a different approach

for me on one of these vehicles.

And I took notes on all that stuff

so that next time I have one,

I can get to the problem more efficiently.

So that's the goal.

That's also why I'm talking about on the podcast.

So hopefully you found that interesting.

Hopefully that all made sense.

If you have something to add,

throw it into the Facebook group.

I'm not on Facebook a ton right now.

The world's a little crazy,

but I try to hop on there every once in a while.

Feel free to shoot me a message if you want.

I do check messenger, but anyways,

I'd like to thank everybody out there for listening.

Hope everybody's doing good.

And with that, let's get out there

and start fixing the world one card at a time.

["The Star-Spangled Banner"]

337: BMW X1 Parasitic Draw Diagnosis Throws Me A Curveball

About this episode

parasitic draw

Bmw X1

Dodge Charger

LED indicator

control module

scan tool

energy diagnostics

BMW TSP

head unit

TSB

F chassis

BDC

relay

Request an Explanation

Want to learn more?

Help improve this episode

More from Automotive Diagnostic Podcast