In this Call Of The Week from Ron Ananian, The Car Doctor Radio Show...
Joe from Pennsylvania has a 2010 Chevy Impala that intermittently gets stuck in Park. The shifter doesn’t have a manual release, and AAA refuses to tow it in that condition. Ron explains the issue likely involves the shift interlock circuit, which depends on the brake light switch, Body Control Module (BCM), and a solenoid controlled by a dark green wire with a white stripe.
Ron advises Joe to:
-
Check if brake lights work when the issue occurs.
-
Test for 12V on the green/white wire when pressing the brake.
-
Use a 194 test bulb inline on that wire to confirm power.
-
Check the ground at the solenoid.
-
Make sure the brake switch was calibrated (BPP calibration) if it was replaced.
If power reaches the solenoid but it doesn’t click, it’s likely the solenoid or ground. If no power, the problem is upstream in the circuit.
Ron emphasizes understanding the circuit before replacing parts.
Full episodes of Ron Ananian, The Car Doctor also available.
Visit us at https://www.cardoctorshow.com
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Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:09):
Well, I guess it's my turn to twelve eight five
to five five six zero nine nine zero zero. By
the way, T shirt sales are booming. I guess everybody
must have bought Ari Atomotive T shirts for mom for
Mother's Day. Now, that can't be it. Maybe Father's Day
is coming up. But yeah, get out the cardoctorshow dot
com if you're looking, and click on the merchandise button
like everybody else. So we're doing well, and don't forget.
(00:30):
Tomorrow fifteen Tacoma will appear in our YouTube feed around
three pm talking about that Fifteenthacoma with a fuel pump issue.
I think it's one of the better videos. We tried
a couple of different things trying to show you guys
a little bit of a variety of what we looked
at to fix that vehicle, and I think it's going
to do well. So that's tomorrow fifteenth Tacoma up on
a YouTube channel and we'll probably post it up to
(00:52):
Facebook two as well, although Facebook's getting a little funny
on how and what they allow, so but just know
that it's out on YouTube. Get out to our YouTube
channel run Nanny and the Car Doctor in case you
haven't let's uh, let's go to Joe in Pennsylvania. A
lot of Pennsylvania calls today, Palla, Hey Joe, how are you?
What can I do for you?
Speaker 2 (01:09):
Yes, good afternoon. Yes, this impalla. It has a different
kind of console shifter than what's listed on YouTube. And
there's no real release button on you have to play
with and you have to push up and down on
a solenoids sometimes to get it out of park. And
what's bad about this? Ron as Triple A refuses to
(01:30):
tow a car when it's stuck in park. Interesting, they
will not do it. They're afraid that they're going to
damage the transmission.
Speaker 1 (01:37):
Interesting, what do they do? What do they do if
it's really stuck in park and you're stuck on.
Speaker 2 (01:40):
The side of the road, Wait till the next day
until somebody comes out with a dolly or whatever. I yeah,
it's crazy, it's ridiculous. I'm sure you've come across it.
Even the local dealer here said he wouldn't do much
for it because it's intermittent. Well, should I do buy
a solenoid for it?
Speaker 1 (01:57):
Under no, So let's let's let's talk about this. Let's
I'm gonna make some assumptions of generality. Okay, so allow
me that. All right, So this is a this is
a ten Impala with a three five right right, and
and the automatic trends won't come out of park exactly.
So when it when it fails, when it won't come
out of park, do you know if the brake lights work?
Speaker 2 (02:21):
Uh, they fixed it once they put used parking. They
put another brake light switch on it too, I guess
and see I bought it from a rebuildable place.
Speaker 1 (02:31):
And it was a car because because that's critical. All right,
if the brake lights work, here's what happens. Right, Joe
gets in the car, He steps on the brake pedal,
The brake lights light up. Joe turns the key on
the the The brake lights switch completes and sends power
up to the body control module. All right, The body
(02:53):
control module sees the brake input request. It thinks Joe
wants to shift out of park because it sees it
also sees park on the on the trans side of life,
and it'll it releases the solenoid. It sends power out
on a separate wire. It sends wire. If you go
down to that shift solenoid, there's a dark green wire
(03:15):
with a white tracer.
Speaker 2 (03:17):
And there's it's different than the ones on the YouTube video.
It's totally different. Even the dealer I went for a
technical service ball and it's totally different with this.
Speaker 1 (03:26):
How's it totally different?
Speaker 2 (03:28):
It doesn't have a release button on the side.
Speaker 1 (03:31):
No, no, no, no, forget that. Look at wiring color?
All right? Do you are you taking this? Are you
taking this console apart on your own?
Speaker 2 (03:39):
Joe? Yes, I took it off because okay.
Speaker 1 (03:43):
So when you when you look at the shift control solenoid,
what color are the two wires at the solenoids?
Speaker 2 (03:50):
Yes, I believe there's a green one there, right, So.
Speaker 1 (03:53):
The dark green wire with the white tracer, and listen,
learn how the circuit works when it's working. Will you
do me that favor?
Speaker 2 (04:02):
So? Yeah, with the deal or, they said the switch
was working, okay, great, another problem was working all right?
Speaker 1 (04:12):
So so but hear me out, all right, I want
you to put your foot on the brake, turn the
key on, and check voltage at that dark green wire
with the white trace. That should be battery voltage. Then,
with the meter still attached to that dark green, white wire,
take your foot off the brake, pedal. You should see
battery voltage go to zero. That shows you that's the
(04:34):
working wire. You with me so far? Yes, Okay, when
the problem happens, do we have power on that dark
green white? First question? Absolute, first question. If we have
power on that dark green white. We've just eliminated seventy
five percent of the circuit. Now we're down to it's
(04:56):
either the solenoid or the ground. Which is the other
wire coming out of the solenoid.
Speaker 2 (05:04):
Well, a couple of times I had to press in
on the solenoid itself to get it gone.
Speaker 1 (05:08):
I understand that, but that's not testing it. I'm talking
about how to test it. Okay, are you able to
test You have a vault meter?
Speaker 2 (05:18):
Yes, I have many of them. Yeah. Okay. They mentioned
there's wiring faults and problems with wire routing, but that
all looked okay.
Speaker 1 (05:27):
Well, but you have to catch it, Joe. You have
to catch it in the act. All right, it's intermittent. Now,
you could you could run a new wire out of
the BCM. But what you want to do is if
you catch it in the act where you're stepping on
the brake pedal switch and you have no power at
(05:49):
that dark green white. Trace it back, get a wiring
diagram that dark green white goes direct to the body computer. Okay,
those wires have been known to break there. They make
a couple of tight turns as they come out. They
have been known to break internally, and sometimes replacement of
that wire does the trick. Sometimes this is a BCM
the actual computer itself, all right, the dish right, Well,
(06:16):
it doesn't matter where it is. It's it's We can't
wish it was somewhere easy. Now, the other question I've
got is when they put a brake light switch in it,
I wonder if they did a brake pedal position calibration.
They call it a b A Baker Paul Paul BPP,
a BPP calibration, and you just scantal to do that.
(06:39):
And if they didn't do that, it will replicate the
same problem as a bad break light switch. The computer
needs to learn pedal position and a new switch replacement
makes sense.
Speaker 2 (06:54):
Well, so I can't just go bypassing it all the time.
That's going to get old.
Speaker 1 (06:58):
It, well, it's gonna get older. It's going to get
old very quickly. This isn't listen, This isn't the hardest
problem in the world to solve, somebody's got to sit
down and understand how the circuit works. And that's that's
all I'm asking you to do, all right. This is
a simple solenoid. It's a power in the ground. Power
comes out of the BCM. BCM looks at you know,
breake pedal switch for input. It looks at park position
(07:21):
because it sees it sees park position when you move
the shifter. There's an indicator on the dish right park, reverse, neutral,
drive and so on right, So that's because the shifter
is talking to the body computer, which is talking to
the instrument panel. What I'm trying to point out is
this isn't a straight shot where the brake pedal switch
moves that solenoid. The brake pedal switch puts input to
(07:42):
the BCM. The BCM looks at other conditions. If they're
all set, it sends voltage out that dark green white
over to the shift solenoid. The shift solenoid pulls in.
It's simple, it really is.
Speaker 2 (07:53):
As Chevy Dealer said, they wouldn't be able to fix it.
Speaker 1 (07:57):
Listen so far well, and that it's true, okay to
a degree. Or somebody's got to take the bull by
the horns. How about how about this? How easy is
it to get to that dark green white wire? Okay,
I go down to your local lotapart store, buy a
one ninety four bulb. Go go get a little sidemark
(08:18):
or bulban socket. Cut the dark green white wire, put
the bulb in between. Cut the dark green white wire
in a place where you can easily solder it back together.
All right, Now, every time you step on the shift
or what's going to happen. If the system's working, it
should light.
Speaker 2 (08:37):
You should also hear it.
Speaker 1 (08:39):
Well, you'll hear it.
Speaker 2 (08:39):
They've had that system early.
Speaker 1 (08:42):
Joe, Joe, You're you're looking too far ahead. Okay, I
love you. You remember the car doctor Nation, but you're
looking too far ahead. I'm talking about diagnosing. You're talking
about expected results on something else. If that bulb lights
and you don't hear the click, yeah, then you've either
got a ground or a solenoid issue. I'm trying to
tell you how to prove it. All right, If you
(09:05):
if you push on the brake pedal and it does
not light, where's the problem that's in the wir ring
or the right or the brake light switch input because
they didn't do a BBP calibration. You get what I'm saying.
Speaker 2 (09:24):
All Right, I guess I'll have to do all that
because I'm afraid i'm gonna get stuck permanently. So all right, Joe,
all right, thank you very much.
Speaker 1 (09:34):
You're very welcome, sir. You'll be well. I'm running any
in the car, doctor, I'll be back right after this
Well, I guess it's my turn to twelve eight five
to five five six zero nine nine zero zero. By
the way, T shirt sales are booming. I guess everybody
must have bought Ari Atomotive T shirts for mom for
Mother's Day. Now, that can't be it. Maybe Father's Day
is coming up. But yeah, get out the cardoctorshow dot
com if you're looking, and click on the merchandise button
like everybody else. So we're doing well, and don't forget.
(00:30):
Tomorrow fifteen Tacoma will appear in our YouTube feed around
three pm talking about that Fifteenthacoma with a fuel pump issue.
I think it's one of the better videos. We tried
a couple of different things trying to show you guys
a little bit of a variety of what we looked
at to fix that vehicle, and I think it's going
to do well. So that's tomorrow fifteenth Tacoma up on
a YouTube channel and we'll probably post it up to
(00:52):
Facebook two as well, although Facebook's getting a little funny
on how and what they allow, so but just know
that it's out on YouTube. Get out to our YouTube
channel run Nanny and the Car Doctor in case you
haven't let's uh, let's go to Joe in Pennsylvania. A
lot of Pennsylvania calls today, Palla, Hey Joe, how are you?
What can I do for you?
Speaker 2 (01:09):
Yes, good afternoon. Yes, this impalla. It has a different
kind of console shifter than what's listed on YouTube. And
there's no real release button on you have to play
with and you have to push up and down on
a solenoids sometimes to get it out of park. And
what's bad about this? Ron as Triple A refuses to
(01:30):
tow a car when it's stuck in park. Interesting, they
will not do it. They're afraid that they're going to
damage the transmission.
Speaker 1 (01:37):
Interesting, what do they do? What do they do if
it's really stuck in park and you're stuck on.
Speaker 2 (01:40):
The side of the road, Wait till the next day
until somebody comes out with a dolly or whatever. I yeah,
it's crazy, it's ridiculous. I'm sure you've come across it.
Even the local dealer here said he wouldn't do much
for it because it's intermittent. Well, should I do buy
a solenoid for it?
Speaker 1 (01:57):
Under no, So let's let's let's talk about this. Let's
I'm gonna make some assumptions of generality. Okay, so allow
me that. All right, So this is a this is
a ten Impala with a three five right right, and
and the automatic trends won't come out of park exactly.
So when it when it fails, when it won't come
out of park, do you know if the brake lights work?
Speaker 2 (02:21):
Uh, they fixed it once they put used parking. They
put another brake light switch on it too, I guess
and see I bought it from a rebuildable place.
Speaker 1 (02:31):
And it was a car because because that's critical. All right,
if the brake lights work, here's what happens. Right, Joe
gets in the car, He steps on the brake pedal,
The brake lights light up. Joe turns the key on
the the The brake lights switch completes and sends power
up to the body control module. All right, The body
(02:53):
control module sees the brake input request. It thinks Joe
wants to shift out of park because it sees it
also sees park on the on the trans side of life,
and it'll it releases the solenoid. It sends power out
on a separate wire. It sends wire. If you go
down to that shift solenoid, there's a dark green wire
(03:15):
with a white tracer.
Speaker 2 (03:17):
And there's it's different than the ones on the YouTube video.
It's totally different. Even the dealer I went for a
technical service ball and it's totally different with this.
Speaker 1 (03:26):
How's it totally different?
Speaker 2 (03:28):
It doesn't have a release button on the side.
Speaker 1 (03:31):
No, no, no, no, forget that. Look at wiring color?
All right? Do you are you taking this? Are you
taking this console apart on your own?
Speaker 2 (03:39):
Joe? Yes, I took it off because okay.
Speaker 1 (03:43):
So when you when you look at the shift control solenoid,
what color are the two wires at the solenoids?
Speaker 2 (03:50):
Yes, I believe there's a green one there, right, So.
Speaker 1 (03:53):
The dark green wire with the white tracer, and listen,
learn how the circuit works when it's working. Will you
do me that favor?
Speaker 2 (04:02):
So? Yeah, with the deal or, they said the switch
was working, okay, great, another problem was working all right?
Speaker 1 (04:12):
So so but hear me out, all right, I want
you to put your foot on the brake, turn the
key on, and check voltage at that dark green wire
with the white trace. That should be battery voltage. Then,
with the meter still attached to that dark green, white wire,
take your foot off the brake, pedal. You should see
battery voltage go to zero. That shows you that's the
(04:34):
working wire. You with me so far? Yes, Okay, when
the problem happens, do we have power on that dark
green white? First question? Absolute, first question. If we have
power on that dark green white. We've just eliminated seventy
five percent of the circuit. Now we're down to it's
(04:56):
either the solenoid or the ground. Which is the other
wire coming out of the solenoid.
Speaker 2 (05:04):
Well, a couple of times I had to press in
on the solenoid itself to get it gone.
Speaker 1 (05:08):
I understand that, but that's not testing it. I'm talking
about how to test it. Okay, are you able to
test You have a vault meter?
Speaker 2 (05:18):
Yes, I have many of them. Yeah. Okay. They mentioned
there's wiring faults and problems with wire routing, but that
all looked okay.
Speaker 1 (05:27):
Well, but you have to catch it, Joe. You have
to catch it in the act. All right, it's intermittent. Now,
you could you could run a new wire out of
the BCM. But what you want to do is if
you catch it in the act where you're stepping on
the brake pedal switch and you have no power at
(05:49):
that dark green white. Trace it back, get a wiring
diagram that dark green white goes direct to the body computer. Okay,
those wires have been known to break there. They make
a couple of tight turns as they come out. They
have been known to break internally, and sometimes replacement of
that wire does the trick. Sometimes this is a BCM
the actual computer itself, all right, the dish right, Well,
(06:16):
it doesn't matter where it is. It's it's We can't
wish it was somewhere easy. Now, the other question I've
got is when they put a brake light switch in it,
I wonder if they did a brake pedal position calibration.
They call it a b A Baker Paul Paul BPP,
a BPP calibration, and you just scantal to do that.
(06:39):
And if they didn't do that, it will replicate the
same problem as a bad break light switch. The computer
needs to learn pedal position and a new switch replacement
makes sense.
Speaker 2 (06:54):
Well, so I can't just go bypassing it all the time.
That's going to get old.
Speaker 1 (06:58):
It, well, it's gonna get older. It's going to get
old very quickly. This isn't listen, This isn't the hardest
problem in the world to solve, somebody's got to sit
down and understand how the circuit works. And that's that's
all I'm asking you to do, all right. This is
a simple solenoid. It's a power in the ground. Power
comes out of the BCM. BCM looks at you know,
breake pedal switch for input. It looks at park position
(07:21):
because it sees it sees park position when you move
the shifter. There's an indicator on the dish right park, reverse, neutral,
drive and so on right, So that's because the shifter
is talking to the body computer, which is talking to
the instrument panel. What I'm trying to point out is
this isn't a straight shot where the brake pedal switch
moves that solenoid. The brake pedal switch puts input to
(07:42):
the BCM. The BCM looks at other conditions. If they're
all set, it sends voltage out that dark green white
over to the shift solenoid. The shift solenoid pulls in.
It's simple, it really is.
Speaker 2 (07:53):
As Chevy Dealer said, they wouldn't be able to fix it.
Speaker 1 (07:57):
Listen so far well, and that it's true, okay to
a degree. Or somebody's got to take the bull by
the horns. How about how about this? How easy is
it to get to that dark green white wire? Okay,
I go down to your local lotapart store, buy a
one ninety four bulb. Go go get a little sidemark
(08:18):
or bulban socket. Cut the dark green white wire, put
the bulb in between. Cut the dark green white wire
in a place where you can easily solder it back together.
All right, Now, every time you step on the shift
or what's going to happen. If the system's working, it
should light.
Speaker 2 (08:37):
You should also hear it.
Speaker 1 (08:39):
Well, you'll hear it.
Speaker 2 (08:39):
They've had that system early.
Speaker 1 (08:42):
Joe, Joe, You're you're looking too far ahead. Okay, I
love you. You remember the car doctor Nation, but you're
looking too far ahead. I'm talking about diagnosing. You're talking
about expected results on something else. If that bulb lights
and you don't hear the click, yeah, then you've either
got a ground or a solenoid issue. I'm trying to
tell you how to prove it. All right, If you
(09:05):
if you push on the brake pedal and it does
not light, where's the problem that's in the wir ring
or the right or the brake light switch input because
they didn't do a BBP calibration. You get what I'm saying.
Speaker 2 (09:24):
All Right, I guess I'll have to do all that
because I'm afraid i'm gonna get stuck permanently. So all right, Joe,
all right, thank you very much.
Speaker 1 (09:34):
You're very welcome, sir. You'll be well. I'm running any
in the car, doctor, I'll be back right after this
Host
Ron Ananian
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