Car locks gone crazy
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Car locks gone crazy
The locks on my car have a mind of their own...The car locks and unlocks at will. Sometimes doing it 4 or 5 times in a row. Has anyone else heard of this. What could cause this???
Thanks for the help.
Thanks for the help.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Yep,,,,you have the FOB flew! 
On a more serious note, you could have a bad FOB. Do you have more tham one FOB?? If so, the bad one should be easy to figure out. They do go bad!
BC
On a more serious note, you could have a bad FOB. Do you have more tham one FOB?? If so, the bad one should be easy to figure out. They do go bad!
BC
Team Owner
Joined: Jul 2006
Posts: 22,181
Likes: 4,178
From: Kannapolis NC
What Lonestar said, turn the passive switch on your fobs (both if you have 2) to the off position. I read a post recently where the guy had an extra fob in his tool box in the garage and it intermittently locked and unlocked his doors. Move them far away and see if you still have the problem.
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
I have already tried all of the obvious things....I guess I should have given a little more information in my original post.
This started a couple of weeks ago when I changed my battery. Within a day or so of installing the new battery the fob stopped working. I tried reprograming it...That worked for a short period of time. When I returned to the car the fob wouldn't work again. I tried reprograming several more times with the same results. I also tried doing it with my other fob. Then I put new batteries into both fobs and tried it again. During one of the programings I stayed in the car for about five minutes thinking through why the car forgot the programing. After a few minutes the locks would unlock...then they would lock again. Sometimes it would lock and unlock four or five or more times. Then it eventually looses the programing and the fobs don't work. The only DTC codes I am getting are U1064 for the LDCM and the RDCM. The ony thing I can think of is that I must have a short someplace, or the DCM's are having trouble communicating with the BCM???
I should also mention that I tried putting the fobs out of range and I have the same problem.
Hopefully the additional information helps.
Last edited by Charley Hoyt; Dec 23, 2006 at 01:44 AM.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
The "U" is a "loss of communication" code and not all that uncommon as long as there are no failures present. Especially if it has an "H" (history) at the end of the number. If you have put the FOBs out of range and you are still getting spurious activation/de-activation of the door locks, there may be issues with the BCM. I think it highly unlikely that both DCMs would fail simultaneously. Have you ever experienced water/moisture on the pass. floorboards in the past? That's where the BCM is located and this has been known to cause all sorts gremlins.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
John
C4's had some ground issues; C5 are ground issues waiting to happen!
GM did a great job on protecting the +12 VDC plugs and connectors with WEATHER TIGHT connectors! They FAILED on the ground side!
If you have a C5 and have electrical problems, you should be looking at the ground path of the circuit in question prior to dropping wads of cash on replacement parts!
You are double prone if you drive your car year around and in increment weather! On the other side of the coin,,,,,your not exempt if you have a garage queen with 5000 miles on the odometer!
Check and clean your grounds!
GM seemed to have made ground (PUN!
) on the C6! Their grounds seem to be rock solid! There an eyelet type of ground vise the connector type.
Check an clean your grounds. A decent cleaning solvent for the connectors is:
A decent corrosion preventive treatment for the exposed ground connectors is:
If you have electrical issue questions, give me a PM!
BC
C4's had some ground issues; C5 are ground issues waiting to happen!
GM did a great job on protecting the +12 VDC plugs and connectors with WEATHER TIGHT connectors! They FAILED on the ground side!
If you have a C5 and have electrical problems, you should be looking at the ground path of the circuit in question prior to dropping wads of cash on replacement parts!
You are double prone if you drive your car year around and in increment weather! On the other side of the coin,,,,,your not exempt if you have a garage queen with 5000 miles on the odometer!
Check and clean your grounds!
GM seemed to have made ground (PUN!
) on the C6! Their grounds seem to be rock solid! There an eyelet type of ground vise the connector type.Check an clean your grounds. A decent cleaning solvent for the connectors is:
A decent corrosion preventive treatment for the exposed ground connectors is:
If you have electrical issue questions, give me a PM!
BC
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Racer
Joined: Sep 2006
Posts: 285
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From: Near Killadelphia Pa
What Lonestar said, turn the passive switch on your fobs (both if you have 2) to the off position. I read a post recently where the guy had an extra fob in his tool box in the garage and it intermittently locked and unlocked his doors. Move them far away and see if you still have the problem.
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Today I checked the BCM and every thing "looked" fine. No moisture...connections looked clean. I also took out the battery and battery tray....some battery acid was evedent...I used baking soda to neutralize the acid....which made a bigger mess. I also checked the connections to the PCM...and they were clean...althought the wires had a lot of dried baking soda on them. I hope I didn't make the problem worse. The condition remains the same...The computer learns the remotes...then after a few minutes the doors unlock and lock repetidly until the code gets erased.
This is really getting frustrating.
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
open the fob, cut the 'shaker' from the circuit board
But first, with the fob STILL does the car unlock/lock on it's own, if the fob moves and it does this then cut the shaker
i have done this to my fob, it was tough, but i got over it
But first, with the fob STILL does the car unlock/lock on it's own, if the fob moves and it does this then cut the shaker
i have done this to my fob, it was tough, but i got over it
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
if the switch is 'off' and the fob makes the car lck/unlck, then cut it
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
It seems to do it regardless of movement. I was experimenting with my number 2 remote today... and with this one I didn't get the repeated locking an unlocking...but after about five minutes the car forgot the code for the remote and the remote stopped working. It is strange that the remote works for a few minutes...and then it stops working????
Le Mans Master
Joined: Sep 2003
Posts: 6,276
Likes: 227
From: Farmington CT
Cruise-In VII Veteran
It seems to do it regardless of movement. I was experimenting with my number 2 remote today... and with this one I didn't get the repeated locking an unlocking...but after about five minutes the car forgot the code for the remote and the remote stopped working. It is strange that the remote works for a few minutes...and then it stops working????
new battery in fob2?
car locks when fob is absolutely still?
then read Bill Curlee's post, sounds like your BCM is taking a bath from the hvac system, very common problem
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Car does lock when the Fob is absolutely still with fob #2. I will have to try Fob #1
I checked the BCM and it is dry and I checked the connections on the BCM and they are fine.
This one is really stumping me...
Last edited by Charley Hoyt; Dec 25, 2006 at 07:51 PM.
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
I checked Fob # 1 and it does lock the car when I move the remote...I cut the shaker....and that worked for a while. Then after a couple of hours the remote stopped controling the car????
Last edited by Charley Hoyt; Dec 26, 2006 at 07:32 PM.
Thread Starter
Safety Car
Joined: Jul 2000
Posts: 3,596
Likes: 37
From: Orange County CA
Any other ideas why the car would forget the code every couple of hours? I can resync by pressing both lock and unlock at the same time and then the remotes work again for a couple of hours. This is strange.