Bad BCM or wiring issue? - Pontiac G6 Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 16 (permalink) Old 10-21-2010, 02:24 PM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Question Bad BCM or wiring issue?

Hello, GM mechanics, just want to aay thanks for being here to help out fellow GM owners. My problem is I own a 2006 pontiac G6 , 4cyl. I added some accessory items into my car about 2weeks ago. I added 2 1600 watt amps, 2 12" subs rated at 800watts each, three 7inch LCD monitors and a 6.5" dvd indash player. Just yesterday I disconnected my battery for a few seconds and reconnected it. Now the odometer reads error, the electronic steering isn't working, the tranny doesn't shift into any higer gear while driving, the speedometer does not work and the engine cooling fans turns on whenever i turn on the A/C but the A/C compressor clutch will not engage. Could i have possible ruined any of the computer modules in the car? I checked the problems and solutions forum but was not able to find an answer to my problem. Any help would greatly be appreciated.
Grand_maestro is offline  
Sponsored Links
Advertisement
 
post #2 of 16 (permalink) Old 10-21-2010, 02:33 PM
Senior Member
 
G6-Lover's Avatar
 
Join Date: Oct 2009
Location: Canada
Posts: 1,063
 
Check this thread someone kinda had the same issue as you, not sure if it fixed it or not but odometer reads "error" but starts

If you had a ODB2 reader you could see what codes its giving..if not may have to take it in to get a diagnostic

2008 Pontiac Sedan - 3.5 V6


Mods so far:
Sylvania Silverstars, Custom Air Intake with Heat shield , 17' Salsa Rims from FastWheels.ca, Lower Grille Chrome Accents, Windows Visors, Hood Deflector, Debadged, Silver Overlays, Eyelids, Recessed Upper Grille, Tinted Tails, GM Strut Bar

Coming Soon - In Order:
Racingline MMI
Racingline Grounding Kit

Updated: 02/22/2011

Best Auto Insurance | Auto Protection Today | FREE Trade-In Quote
G6-Lover is offline  
post #3 of 16 (permalink) Old 10-22-2010, 12:36 PM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Smile G6 computer problem.

Thanks for the reply G6 lover. I took my car to the local GM dealer and they told me that it would cost $110 per hour to perform a diagnostic which could take anywhere from 3-5 hours. And afterwards they would tell me what part I would need to replace which could be an extra $300-$400. And I am as broke as ever right now. Would you recommend that I take it to a second hand mechanic? I am at a lost for options right now. But I will take a look at the thread you sent me.
Grand_maestro is offline  
post #4 of 16 (permalink) Old 10-22-2010, 12:38 PM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Smile G6 problem

The link to the post you sent me did not contain any answers to the problem i had. But thanks for replying.
Grand_maestro is offline  
post #5 of 16 (permalink) Old 10-22-2010, 01:50 PM
Senior Member
 
Join Date: Dec 2005
Posts: 606
 
Did you by any chance disconnect the battery with key on, that can damage a lot of electronics.
slls is offline  
post #6 of 16 (permalink) Old 10-22-2010, 06:47 PM
Senior Member
 
G6-Lover's Avatar
 
Join Date: Oct 2009
Location: Canada
Posts: 1,063
 
Yeah i didnt think it had the exact problem but might of been somewhere to start haha but yeah it is expensive its almost cheaper to just buy your own reader

2008 Pontiac Sedan - 3.5 V6


Mods so far:
Sylvania Silverstars, Custom Air Intake with Heat shield , 17' Salsa Rims from FastWheels.ca, Lower Grille Chrome Accents, Windows Visors, Hood Deflector, Debadged, Silver Overlays, Eyelids, Recessed Upper Grille, Tinted Tails, GM Strut Bar

Coming Soon - In Order:
Racingline MMI
Racingline Grounding Kit

Updated: 02/22/2011

Best Auto Insurance | Auto Protection Today | FREE Trade-In Quote
G6-Lover is offline  
post #7 of 16 (permalink) Old 10-23-2010, 09:20 PM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Smile Computer issue

Slls, I think i may have disconnected and reconnected the battery with the Key on. And if i had possibly damaged some electronics, do you have any idea which ones i may have damaged?
Grand_maestro is offline  
post #8 of 16 (permalink) Old 10-26-2010, 11:31 AM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Damaged electronics?

Is it really possible to damage my BCM, PCM by connecting the positve lead to the battery terminal while elaving the key on?
Grand_maestro is offline  
post #9 of 16 (permalink) Old 10-26-2010, 12:35 PM
Junior Member
 
Join Date: Jun 2010
Posts: 15
 
Most certainly. When working on a new car it is always worth taking the extra effort to make sure you don't damage anything. Diconnecting a battery is always good, but leaving the key on opens the sercuit.

Hope this isn't what happened to you, but it very could be. Try going by a junk yard and see if they will let you try a computer. Plug and play.
Blackhawk131 is offline  
post #10 of 16 (permalink) Old 10-27-2010, 01:09 AM
Professional geek
 
Join Date: Dec 2009
Location: SoCal
Posts: 433
 
The symptoms you describe sound like a Body Control Module (BCM) issue.

Try this:

First, with the key out of the ignition (to prevent further problems!), disconnect the NEGATIVE battery cable.

Next, disconnect the power to all the new electronics you added. Whether it is pulling out the fuse, removing the wire, whatever, disconnect the power completely. Note that turning off the power switch is not the same as disconnecting the power.

Now, reconnect the battery, and see if the car acts normally. If it does not, it's possible that you have a damaged BCM. But, it's also possible that you have a bad or discharged battery, especially if you left the doors open for a while while you were connecting all those electronics.

If the car does act normally, turn the key off. Reconnect one of the new devices at a time. If you pulled a fuse, just reinsert the fuse. If you disconnected a wire, it is probably safest to disconnect the battery again (always the NEGATIVE terminal) before reconnecting the wire. Note that when disconnecting the battery, you should leave it disconnected for at least 30 seconds before reconnecting it; this allows the electronic devices in the car to reset properly after having their power removed and then reconnected.

If the car starts acting funny after reconnecting one of the devices, you've found a problem. You should make sure to check all the remaining devices just to make sure there's not more than one.

Note on Blackhawk131's suggestion to try swapping modules from a junkyard: Don't. The modules cannot be swapped without being reprogrammed by the dealer, and they very likely would not touch a car with a used BCM installed - not that you could get it there without towing it in. Used modules are most certainly not plug and play (more like plug and pray, and your prayers will not be answered!).

Good luck!

~ MattInSoCal

Last edited by MattInSoCal; 10-31-2010 at 03:06 PM.
MattInSoCal is offline  
post #11 of 16 (permalink) Old 10-31-2010, 08:20 AM
Senior Member
 
Join Date: Dec 2005
Posts: 606
 
Quote:
Originally Posted by Grand_maestro View Post
Is it really possible to damage my BCM, PCM by connecting the positve lead to the battery terminal while elaving the key on?
That is why I mentioned it, has to do with any electronics. You are not suppose to disconnect any electronics with power still applied.

Transmission would be PCM, maybe BCM for others. Have dealer tell you what you need, they would need to flash a new unit anyways.
slls is offline  
post #12 of 16 (permalink) Old 11-04-2010, 11:16 AM Thread Starter
Junior Member
 
Join Date: Oct 2010
Posts: 6
 
Smile Thanks MATTINSOLCAL and SllS.

I just wanted to take the time to thank you guys for taking the time to post information that would help me in my problem; thanks alot. And you both were right, i had a bad BCM which needed to be reprogrammed by the dealer which cost me $241 including tax deduction with my dad's dealer number.

And MATTINSOLCAL i will save your information as it may come in handy in the future.
Grand_maestro is offline  
post #13 of 16 (permalink) Old 09-02-2011, 09:35 AM
Junior Member
 
Join Date: Jun 2010
Posts: 15
 
Well after some time troubleshooting I have finally resolved my problem. So let me do my best to explain the events and the solution. Hope this helps some of you, but clearly there is a problem with the electric power steering.

Before a long trip I decided to do plugs, wires and O2 sensors before making my long road trip and due to the fact that the car was in need of a turn up. Now I could not get off the back plug wires (I cannot stress putting a lot of Dielectric Grease in the plug boots to prevent this from happening) so I decided to wait to get them off till I returned from my trip. Car drove there and back with no problems. Once I returned I removed the alternator (while doing so the positive cable sparked on the block) to gain better access to the back of the motor. I then disconnected the battery which you should do anyhow, but was fairly sure this didn't cause any problems.

After all put back together my wife called several days later saying the car was acting weird. She told me that when she gave it gas all of the gauges would flash and steering go very tight. Of course at first I thought of the spark and how what problems could I have caused. Well about a week later we received a letter from GM stating that if you are having these problems then have the column replaced. After doing so the car drove so much better but the problem started again very shortly afterwards. I didn't want to bother the dealer again so I started reading online and someone said that the tensioner was the problem. I could see this if the belt is slitting and then the alternator wouldn't work correctly. So it was replaced with same result.
Now so far I know that I lose power steering under full acceleration and under a load. Also I knew by this point that the problem didnít occur if it was 60 degree or cooler outside. I then knew this had to be electrically and only thing that it could have been was alternator and battery. Both tested fine in the car.

Solution: I felt that because the car ran on the alternator when running I had to start there. Once this was replaced I have not had a problem since. I did go ahead and replace the battery latter because I felt it could have been affected with the weak alternator for so long. I guess once it got hot enough it just was not efficient any more. Hope this helps someone else.

**Problem noticed when mid to full acceleration(passing cars) or running cruise control and going up a slight hill that caused a load on the car causing mild acceleration.

Because the car needed a little more electrically power, the alternator could not keep up and something as demanding as a electric power steering would fail.

-Grant
Blackhawk131 is offline  
post #14 of 16 (permalink) Old 09-02-2011, 02:43 PM
OOBER SUPER MEMBER
 
Join Date: Jul 2011
Posts: 2,388
 
Quote:
Originally Posted by Blackhawk131 View Post
Well after some time troubleshooting I have finally resolved my problem. So let me do my best to explain the events and the solution. Hope this helps some of you, but clearly there is a problem with the electric power steering.

Before a long trip I decided to do plugs, wires and O2 sensors before making my long road trip and due to the fact that the car was in need of a turn up. Now I could not get off the back plug wires (I cannot stress putting a lot of Dielectric Grease in the plug boots to prevent this from happening) so I decided to wait to get them off till I returned from my trip. Car drove there and back with no problems. Once I returned I removed the alternator (while doing so the positive cable sparked on the block) to gain better access to the back of the motor. I then disconnected the battery which you should do anyhow, but was fairly sure this didn't cause any problems.

After all put back together my wife called several days later saying the car was acting weird. She told me that when she gave it gas all of the gauges would flash and steering go very tight. Of course at first I thought of the spark and how what problems could I have caused. Well about a week later we received a letter from GM stating that if you are having these problems then have the column replaced. After doing so the car drove so much better but the problem started again very shortly afterwards. I didn't want to bother the dealer again so I started reading online and someone said that the tensioner was the problem. I could see this if the belt is slitting and then the alternator wouldn't work correctly. So it was replaced with same result.
Now so far I know that I lose power steering under full acceleration and under a load. Also I knew by this point that the problem didn’t occur if it was 60 degree or cooler outside. I then knew this had to be electrically and only thing that it could have been was alternator and battery. Both tested fine in the car.

Solution: I felt that because the car ran on the alternator when running I had to start there. Once this was replaced I have not had a problem since. I did go ahead and replace the battery latter because I felt it could have been affected with the weak alternator for so long. I guess once it got hot enough it just was not efficient any more. Hope this helps someone else.

**Problem noticed when mid to full acceleration(passing cars) or running cruise control and going up a slight hill that caused a load on the car causing mild acceleration.

Because the car needed a little more electrically power, the alternator could not keep up and something as demanding as a electric power steering would fail.

-Grant
You overloaded the stock alternator with all that gear. You need a high-output alt, if you can find one.

http://mechman.com/index.php/blog/it...-can-make.html

Last edited by greenman; 09-02-2011 at 03:02 PM.
greenman is offline  
post #15 of 16 (permalink) Old 09-02-2011, 03:40 PM
Senior Member
 
reverttheclown's Avatar
 
Join Date: May 2010
Location: Syracuse, NY
Age: 25
Posts: 911
 
Garage
@greenman - the OP had all the tech gear, not blackhawk

2006 Pontiac G6 V6 3500L
Crimson Red
reverttheclown is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac G6 Forum > Technical Discussion & Modifications > Problems and Solutions

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac G6 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
BCM (Body Control Module) Location JCR Problems and Solutions 4 09-19-2010 05:56 PM
Replace BCM on 08 GTP zipzip2010 Problems and Solutions 6 06-19-2010 03:12 PM
Replace BCM on 08 GTP zipzip2010 Powertrain Performance Modifications 2 06-18-2010 05:13 AM
Wiring Headlights together Crystalm8489 Appearance Modifications and Lighting 3 06-15-2009 11:37 PM
Good News-Bad News---Bad News-Wife says let's trade the "G" WhoaThereBigFella Members' Rides 2 06-11-2007 07:12 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome