Bought, wrecked, rebuilding a 2009 LMM

2004LB7

Super Moderator
Staff member
Dec 15, 2010
7,202
2,265
113
Norcal
The Headquarters moved. I don't know if the moved both stores or just closed them. I just know they settled the CARB thing in 2021 like PPE and they said F-You to CA.
Looking at Google maps and it now shows that branch as "Duramax service center". So possibly rebrand or sold it
 
  • Like
Reactions: 1FastBrick

malibu795

misspeelleerr
Apr 28, 2007
8,371
650
113
42
in the buckeye state
Sent this to autel..
I have what appears to BCM issues on a 2009 GM vehicle. What platform (s) allows my to read/clear/function test BCM codes?
Ideally I'd like one that does not need a subscription but not agay subscription versions..

Her reply
I hope this message finds you well. Could you kindly confirm if your issue has been resolved? We're here to provide any additional assistance you may need to ensure everything is working properly for you
In which I sent

Sorry I thought I was pretty clear. I am asking what diagnostic platforms can read clear and function test a GM Body control module on a 2009 GM vehicle?
If it can do U and C codes that would be helpful

Maybe I'm corporate stupid 🤷🏻‍♂️
 
  • Haha
Reactions: 2004LB7

1FastBrick

Well-known member
Dec 1, 2016
2,673
1,173
113
Junkyard
Sent this to autel..
I have what appears to BCM issues on a 2009 GM vehicle. What platform (s) allows my to read/clear/function test BCM codes?
Ideally I'd like one that does not need a subscription but not agay subscription versions..

Her reply
I hope this message finds you well. Could you kindly confirm if your issue has been resolved? We're here to provide any additional assistance you may need to ensure everything is working properly for you
In which I sent

Sorry I thought I was pretty clear. I am asking what diagnostic platforms can read clear and function test a GM Body control module on a 2009 GM vehicle?
If it can do U and C codes that would be helpful

Maybe I'm corporate stupid 🤷🏻‍♂️
Unfortunately It's a Chinese based Scan tool so it probably a translation issue for whomever is reading and responding to the emails.... There is a US based office you can try. Even have a US number you can try and call

1735841139815.png
 

malibu795

misspeelleerr
Apr 28, 2007
8,371
650
113
42
in the buckeye state
Drove it to work today, get ready to go home.. truck is dead. Jump it with the semi. Starts up, smell burning plastic shortly after.. find protective shields on BAT cable post on the on the alternator smoking. Nothing is loose or obviously rubbing. Pull the 2 wire quick connect to de activate the Alt.

Which probably what caused electrical issues going home or dead battery (s). Which was random TCC lock/UNLOCK, AND "MX" in the PRDML area randomly flashing along with a clicking noise under the dash.
Pulled a U0100 code when I got home before I disconnected the batteries. The autel wouldn't connect but the innova did..
Ran in 5th due to the 5-600rpm drop/raise id see in 6th with TCC lock/unlock.. at same speed. Getting a better TC can't get here soon enough 😔
Short clip.
Source: https://youtu.be/PGGB9frvRok?feature=shared


Glad I own more than 1 running.. vehicle take my suburban in tomorrow
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
7,202
2,265
113
Norcal
Don't see how pulling the alternator control connector would stop that. The diodes should prevent the current from flowing from the batteries to the alternator. And if the diodes are shorted put then pulling the connector wouldn't do anything. Are you thinking the alternator was outputting too high voltage and thus current into the batteries? Or one or more cells in the batteries are shorted and thus drawing excessive current, so shutting off the alternator will protect it?

I'd let the batteries sit overnight disconnected and check the voltage in the morning. Of course you need to have them fully charged first before doing the resting voltage check. So it you had to drive home with no alternator then put the batteries on a charger first
 

malibu795

misspeelleerr
Apr 28, 2007
8,371
650
113
42
in the buckeye state
I killed the Alt to reduce the possibility burning the truck down due to the battery wire smoking on the alternator bat post.. it stopped smoking when I killed the alternator.. figured 2 batteries are cheaper than a burned out truck, and substantially less eventful.

Alt is a 160A that I've had for a while.. post connection was not loose Alt or the junction block on the PS firewall why it looks over heated IDK.

Lack of proper voltage could have caused the other electrical issues with the TCC/clicking and gear indicator.

Maybe there's some ground(s) I'm missing.
 

Attachments

  • IMG_20250102_202957649.jpg
    IMG_20250102_202957649.jpg
    333.2 KB · Views: 9
  • IMG_20250102_203001778.jpg
    IMG_20250102_203001778.jpg
    280 KB · Views: 9
  • IMG_20250102_203008652.jpg
    IMG_20250102_203008652.jpg
    192.8 KB · Views: 9

1FastBrick

Well-known member
Dec 1, 2016
2,673
1,173
113
Junkyard
Is that the Fusible link? I believe It goes from back of alternator post to Fuse holder. Mega 175 Amp

I know a friend of mine had an issue on a GMT400 with his. It turned out to be a connection/ corrosion issue. Of course he also had to replace the alternator because it partially melted it. But luckily it was under warranty at his local parts store.

2009 battery supply fusible link.jpgFusible link info.jpg
 
Last edited:

malibu795

misspeelleerr
Apr 28, 2007
8,371
650
113
42
in the buckeye state
There is a 175a maxi fuse for the Alt charge wire. And it's located on the PS firewall..
AFAIK there's no fusible link in the cable.. that would be news to me on either of those locations
 

1FastBrick

Well-known member
Dec 1, 2016
2,673
1,173
113
Junkyard
There is a 175a maxi fuse for the Alt charge wire. And it's located on the PS firewall..
AFAIK there's no fusible link in the cable.. that would be news to me on either of those locations
You are probably right since it goes to a maxi fuse.
The GMT 400 and GMT 800 Gas versions are different.
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
7,202
2,265
113
Norcal
PS battery is D-E-A-D after charging for 12+ hrs it dropped from 13V to 12V in under 1HR and it's all wet as well looks like it boiled
I was guessing so. Had to be somewhere that current was going. Check it again after sitting overnight. If it's somewhere around 10.5 to 11 volts then you lost one of the cells