I suspect BCM... thoughts?
- Thread starter TrybalRage
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
TrybalRage
Member
- Joined
- Jun 13, 2009
- Posts
- 94
- Reaction score
- 76
Well, no bueno. Started up all afternoon yesterday fine sitting in the sun. Went out this afternoon, no start.
What I'm dealing with - note the no indicator of the shift position. That's always a dead giveaway it won't start.
Battery voltage showed 12.2. Little low considering I just charged it on Sunday. Removed positive cable (it's easier to get to on these stupid things), waited 5 seconds, reattached it, fired right up.
What I'm dealing with - note the no indicator of the shift position. That's always a dead giveaway it won't start.
Battery voltage showed 12.2. Little low considering I just charged it on Sunday. Removed positive cable (it's easier to get to on these stupid things), waited 5 seconds, reattached it, fired right up.
Have you removed the positive battery cable and mega fuse and inspected for internal corrosion/ dirty terminals? Or removed the under hood fuse panel and looked for corrosion underneath where it plugs in?
donjetman
Full Access Member
- Joined
- Oct 22, 2018
- Posts
- 1,573
- Reaction score
- 2,810
12.2v is half dead
40% to 50% SOC-state of charge
TrybalRage
Member
- Joined
- Jun 13, 2009
- Posts
- 94
- Reaction score
- 76
A the battery everything looks clean as a whistle. No corrosion, no buildup of any kind. I have not inspected the other end at the fuse box.
TrybalRage
Member
- Joined
- Jun 13, 2009
- Posts
- 94
- Reaction score
- 76
Right, which originally had me chasing a parasitic draw for the past 6 months. But when I test across all the fuses like this video shows, all show 0.
And if it was just low voltage, why does it immediately start after a quick disconnect/reconnect? Makes no sense to me.
EDIT: I tested across all the inside and inside fuses that I could, EXCLUDING the J-case fuses cause I couldn't figure out how to do so since the caps don't allow access the same way.
The fuse box will detach with the 2 big latches and pull straight up, you’ll be able to see underneath where everything plugs in. Disconnect the battery first. There’s been plenty of people who have found corrosion in those connections. The mega fuse is on the firewall, that’s where the positive cable goes to.
TrybalRage
Member
- Joined
- Jun 13, 2009
- Posts
- 94
- Reaction score
- 76
I'll take a look then. The mega fuse on mine is right at the positive terminal, part of a bracket that includes the terminal connection.
TrybalRage
Member
- Joined
- Jun 13, 2009
- Posts
- 94
- Reaction score
- 76
Ooh, we've got new info. I'm pulling U0101 and U0102 codes (lost communication with TCM and Transfer case). Well that would explain the dash errors.
Looks like I've got some deeper inspections to do. I found a longer/more detailed TSB document here: https://static.nhtsa.gov/odi/tsbs/2012/SB-10043829-6448.pdf
So the short version is, every single harness everywhere in the vehicle could have been rubbed through somewhere and everywhere all at once. Yay me.
Anybody want a 2500 suburban? Ugh.
Looks like I've got some deeper inspections to do. I found a longer/more detailed TSB document here: https://static.nhtsa.gov/odi/tsbs/2012/SB-10043829-6448.pdf
So the short version is, every single harness everywhere in the vehicle could have been rubbed through somewhere and everywhere all at once. Yay me.
Anybody want a 2500 suburban? Ugh.
Chiming in on this thread since I'm having the same issue on my 2007 Escalade. Normally the threads I find from google are a decade old so it's nice to see a current one.
I had exactly the same issues; no crank no start with the missing prndl indicator, various other circuits not working like exterior and interior lights, radio, tailgate, etc. Never had low battery voltage with those symptoms.
Like you, disconnecting the battery fixed everything but sometimes it would take a dozen or more tries to "reset" it. I could never figure out the cause.
At first I suspected a ground issue but I had gone through all my grounds, plus the fact that since I have a high powered audio system (5000W RMS+) all my grounds are absolutely solid. 4/0 OFC under the hood and dual 1/0 OFC to my rear lithium battery. Amplifiers grounded with the same. I had removed the factory battery ground since I no longer had an underhood battery. In addition to the factory grounds, I had added block to frame, block to body, and body to frame under the hood and had battery to frame and battery to body in the rear.
Then I found some info on the junction block (underhood fuse block) having issues with corrosion or bad board traces or something. My coworker had the same issue with his Tahoe. I removed it, checked for any loose terminals, cleaned it up and reseated it. That managed to fix my issue again for a bit, but I still had to disconnect the battery a few times to fix it again.
Last week, I had an occurrence of the issue that likely completely killed several cells of my lithium bank (dropped me all the way down to less than 6V on a 13.8V bank), or several of my cells died all at once and caused the issue too occur(?). Replaced it with an AGM and no amount of fiddling with the ground cable or junction block fixed it. So I replaced both the junction block and the base since some of the tangs that hold the harness connectors were broken. Still have the same issue.
Today, I went out with my tech 2 + CANdi module and checked what I could (battery was at 11.8V from messing with everything so much so I'm waiting for it to charge in a few hours). Turns out I had connection with the TCM, liftgate, radio, ecm, and all the stuff I thought wasn't working for whatever reason. The only thing I couldn't connect with was the BCM. BCM controls a bunch of the stuff that isn't working and also I think the transfer case module and some other things related to actually starting the truck. I still have to find the wiring diagrams. I'll be going back out in a few hours to investigate.
So your issue still may be grounds, so definitely disconnect everything, sand down to shiny metal, apply dielectric grease for protection, and also check the resistance of the wire to see if there's any internal corrosion. I'm not an electrician but my grounds were in the 0.1 to 2 ohm range, including through the frame from back to front. I think I read somewhere that less than 5 ohms is acceptable, but someone should correct me if I'm wrong.
Or your issue could still be BCM, since GM was very bad with soldering (just ask anyone with a 98-00 Corvette that had ABS issues) and that would make sense why you have the issue more often in direct sun rather than in the garage.
But definitely check all your grounds first and I hope you have some good news when you reply. I hope I have some too.
I had exactly the same issues; no crank no start with the missing prndl indicator, various other circuits not working like exterior and interior lights, radio, tailgate, etc. Never had low battery voltage with those symptoms.
Like you, disconnecting the battery fixed everything but sometimes it would take a dozen or more tries to "reset" it. I could never figure out the cause.
At first I suspected a ground issue but I had gone through all my grounds, plus the fact that since I have a high powered audio system (5000W RMS+) all my grounds are absolutely solid. 4/0 OFC under the hood and dual 1/0 OFC to my rear lithium battery. Amplifiers grounded with the same. I had removed the factory battery ground since I no longer had an underhood battery. In addition to the factory grounds, I had added block to frame, block to body, and body to frame under the hood and had battery to frame and battery to body in the rear.
Then I found some info on the junction block (underhood fuse block) having issues with corrosion or bad board traces or something. My coworker had the same issue with his Tahoe. I removed it, checked for any loose terminals, cleaned it up and reseated it. That managed to fix my issue again for a bit, but I still had to disconnect the battery a few times to fix it again.
Last week, I had an occurrence of the issue that likely completely killed several cells of my lithium bank (dropped me all the way down to less than 6V on a 13.8V bank), or several of my cells died all at once and caused the issue too occur(?). Replaced it with an AGM and no amount of fiddling with the ground cable or junction block fixed it. So I replaced both the junction block and the base since some of the tangs that hold the harness connectors were broken. Still have the same issue.
Today, I went out with my tech 2 + CANdi module and checked what I could (battery was at 11.8V from messing with everything so much so I'm waiting for it to charge in a few hours). Turns out I had connection with the TCM, liftgate, radio, ecm, and all the stuff I thought wasn't working for whatever reason. The only thing I couldn't connect with was the BCM. BCM controls a bunch of the stuff that isn't working and also I think the transfer case module and some other things related to actually starting the truck. I still have to find the wiring diagrams. I'll be going back out in a few hours to investigate.
So your issue still may be grounds, so definitely disconnect everything, sand down to shiny metal, apply dielectric grease for protection, and also check the resistance of the wire to see if there's any internal corrosion. I'm not an electrician but my grounds were in the 0.1 to 2 ohm range, including through the frame from back to front. I think I read somewhere that less than 5 ohms is acceptable, but someone should correct me if I'm wrong.
Or your issue could still be BCM, since GM was very bad with soldering (just ask anyone with a 98-00 Corvette that had ABS issues) and that would make sense why you have the issue more often in direct sun rather than in the garage.
But definitely check all your grounds first and I hope you have some good news when you reply. I hope I have some too.
