When driving the door locks unlock and lock

Tiny
AH8007
  • MEMBER
  • 2006 CHEVROLET IMPALA
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
When I am driving my sedan door locks unlock and lock. Car seems to be going in and out of park to on my instrument cluster while driving.

What do you think can cause this?

I attached a video below
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Saturday, April 25th, 2020 AT 7:52 AM

17 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

I watched the video and noted that the shift indicator would briefly jump to P when the locks were actuated. When you shift the car out of Park the doors automatically lock. There is a sensor in your shifter assembly which detects when the shifter has moved from park and then this locks your doors. On the other hand, the automatic door locks are controlled by the body control module which could be failing as well.

There is a door lock relay, but it is part of a printed circuit board and not replaceable.

Before we jump the gun and start checking or replacing everything, lets start by checking for a weak ground. If you look at the pic I attached, it shows where the ground for the circuit is located. Check that first.

Let me know what you find.

Joe
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Saturday, April 25th, 2020 AT 8:41 PM
Tiny
AH8007
  • MEMBER
Which one is A pillar?
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Sunday, April 26th, 2020 AT 5:45 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I attached a pic below to help. The arrow I added points to the front of the vehicle.

Let me know if this helps.

Take care,
Joe
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Sunday, April 26th, 2020 AT 8:12 PM
Tiny
AH8007
  • MEMBER
Ground came back good.
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Monday, April 27th, 2020 AT 4:06 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Then we need to have the computer scanned to see if there are diagnostic trouble codes that could relate to the transmission range sensor, shifter assembly, lock relay, or an issue with the body control module.

I realize not everyone has a scanner but often times a parts store will do it free of charge. Have that done and let me know if any codes are present.

Take care,
Joe
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Monday, April 27th, 2020 AT 8:06 PM
Tiny
AH8007
  • MEMBER
After scanning there are no codes stored on the vehicle.
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Monday, April 27th, 2020 AT 10:16 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I have to be honest. I spoke with another tech and we both feel it is related to the body control module (BCM). He is recommending a specific type of scan which check the can buss system. Watch this video:

https://www.youtube.com/watch?v=u-4syLc-ifQ&feature=youtu.be

Joe

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Tuesday, April 28th, 2020 AT 7:53 PM
Tiny
AH8007
  • MEMBER
I replaced the shift assembly and it's still doing the same thing. I have a donor car that does not do this. So the parts are going to be free.
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Thursday, April 30th, 2020 AT 11:46 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Can you check the body control in both vehicle and see if they have the same part number?

I attached a pic of location. The only concern is reprogramming. This will need done if replaced.

Joe
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Thursday, April 30th, 2020 AT 9:11 PM
Tiny
AH8007
  • MEMBER
The BCM didn't fix it.
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Thursday, May 7th, 2020 AT 4:48 PM
Tiny
AH8007
  • MEMBER
It seems to do it when I hit bumps in the road.
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Thursday, May 7th, 2020 AT 4:49 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
It sounds like a simple connection issue, but where is it located. I looked through to identify different things, and I really feel you need to have it scanned with a can scanner. It will identify where the fault lies.

Joe
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Thursday, May 7th, 2020 AT 9:21 PM
Tiny
KEN L
  • ADMIN
Yes, it sounds like a ground issue. Can you start the car without driving it and move wiring harnesses around? PCM and BCM to see if you can get it to act up?
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Friday, May 8th, 2020 AT 12:10 PM
Tiny
AH8007
  • MEMBER
No it does not do it when I shake the harness. Only seems to do it when the car is at operating temperature and when hitting bumps. Lights in the car also seem to flicker when it does it too.
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Thursday, May 14th, 2020 AT 5:19 AM
Tiny
KEN L
  • ADMIN
I am wondering if the alternator is throwing AC voltage. we can be sure by following this guide:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please run down this guide and report back.
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Thursday, May 14th, 2020 AT 12:26 PM
Tiny
AH8007
  • MEMBER
Turned out to be the red positive battery wire was grounding out on the pulley on the car.
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Wednesday, May 20th, 2020 AT 4:14 AM
Tiny
KEN L
  • ADMIN
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help. Can you please shoot a quick video with your phone so we can see what's going on? That would be great. You can upload it here with your response.
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Wednesday, May 20th, 2020 AT 10:47 AM

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