no start & theft deterrent light, after battery swap

[gat0r]

howdy all

i'm having an issue after swapping out my battery

yesterday w/o warning my '15 burb wouldnt start
hooked up jumper box & it fired right up
alternator gauge looked ok & ran my errand. all the auto stores were closed

this morning, same thing
so figure its about time for a new battery (4 years & didnt have this issue then)
so bought new battery

swap it out on my lunch break & think all is well.
...until i try & go to dinner. it wont start. i rec'v pop up msg about theft deterrent system.


i disconnect neg. battery cable for about 10 min.
reconnect & same issue.
(all connectors are clean)

saw a video mention while in vehicle hold down lock & unlock buttons on keyfob for 3-4 seconds.
recv a few flashes on mirrors & security dash light
still wont start


i disconnect neg. & pos. battery cable for about 20 min.
reconnect & same issue.

keyfob & door handle lock/unlock work fine
as does radio & everything else.


@ one point, it asked me to open & then close my drivers window
followed by opening & then close my passenger window
what is that about?


so i tried remote start for sh!ts & giggles, cranks right up (w/ both keyfobs)
{1 keyfob is new within last year
& main keyfob, changed battery today, just to be safe.}
go to apply brake & press start button... it dies & pop up msg about theft deterrent system.



even thought to unlock & lock w/ keyfob.... then unlock w/ backup key
still wont start


found multiple posts about touching pos & neg cable (after disconnecting) to discharge any residual charge
reconnect & same issue.


finally think, although remote start works... maybe battery is just a hair under required charge.
hook up battery charger for 15 min
still wont start


found thread on another forum, said to press start button in accessory mode. leave it for 10 minutes & see if security light goes out.
it auto turns off prior to 10 min. so cant test/validate this option.


currently, unhooked pos & neg cables & letting it sit overnight
b4 i try another time... then call dealership & try to talk to mechanic


*don't think it needs relearn of keyfobs, nor a BCM issue.
also not a starter motor issue
.... as i can lock/unlock & remote start it w/ both keyfobs


tried searching a few diff options, but seems i have already tried what i found
[theft deterrent / wont start / battery cable / ]


thoughts/suggestions?

 

[swathdiver]

The following comment is not necessarily directed to the OP, if the shoe fits, wear it:

Always disconnect the negative cable first and attach it last when replacing the battery. Same for attaching and removing jumper cables.

 

[gat0r]

that's what i did
as the neg cable is easiest to deal with

 

[CMoore711]

Same thing happened when I swapped the battery on my wife’s ‘19 Escalade ESV. But I was also getting a “hood open” message due to the hood latch sensor. Even though the hood was clearly closed (freaked my wife out).

I reset the battery cable as mentioned above. Still threw a couple errors and then after 1-2 days they all just randomly went away…

Right wrong or indifferent; I chalked it up to the vehicle adjusting from going from an old tech flooded battery to a new AGM…. I had also swapped my old ‘15 Yukon XL Denali to an AGM battery with zero issues and it operated just fine. Maybe the Caddy was more sensitive to the adjustment?

 

[Doubeleive]

howdy all

i'm having an issue after swapping out my battery

yesterday w/o warning my '15 burb wouldnt start
hooked up jumper box & it fired right up
alternator gauge looked ok & ran my errand. all the auto stores were closed

this morning, same thing
so figure its about time for a new battery (4 years & didnt have this issue then)
so bought new battery

swap it out on my lunch break & think all is well.
...until i try & go to dinner. it wont start. i rec'v pop up msg about theft deterrent system.


i disconnect neg. battery cable for about 10 min.
reconnect & same issue.
(all connectors are clean)

saw a video mention while in vehicle hold down lock & unlock buttons on keyfob for 3-4 seconds.
recv a few flashes on mirrors & security dash light
still wont start


i disconnect neg. & pos. battery cable for about 20 min.
reconnect & same issue.

keyfob & door handle lock/unlock work fine
as does radio & everything else.


@ one point, it asked me to open & then close my drivers window
followed by opening & then close my passenger window
what is that about?


so i tried remote start for sh!ts & giggles, cranks right up (w/ both keyfobs)
{1 keyfob is new within last year
& main keyfob, changed battery today, just to be safe.}
go to apply brake & press start button... it dies & pop up msg about theft deterrent system.



even thought to unlock & lock w/ keyfob.... then unlock w/ backup key
still wont start


found multiple posts about touching pos & neg cable (after disconnecting) to discharge any residual charge
reconnect & same issue.


finally think, although remote start works... maybe battery is just a hair under required charge.
hook up battery charger for 15 min
still wont start


found thread on another forum, said to press start button in accessory mode. leave it for 10 minutes & see if security light goes out.
it auto turns off prior to 10 min. so cant test/validate this option.


currently, unhooked pos & neg cables & letting it sit overnight
b4 i try another time... then call dealership & try to talk to mechanic


*don't think it needs relearn of keyfobs, nor a BCM issue.
also not a starter motor issue
.... as i can lock/unlock & remote start it w/ both keyfobs


tried searching a few diff options, but seems i have already tried what i found
[theft deterrent / wont start / battery cable / ]


thoughts/suggestions?

if you have a scanner/code reader, try putting it in accessory mode and clear/reset the computer even though there may be no codes.
I am somewhat convinced the k2's are possessed, lol
had the battery off on the wifes 16 a few days ago to change a port and reconnected, all was well/normal as expected on these trucks
i.e. you have to roll the driver/passenger window up/down holding the button for a additional 5 seconds, drive in a few circles to re-calibrate the compass and drive up to 5 miles to reset the ambient temp sensor (that is all 100% normal)
what was not normal is the next day her "service security system" popped up on the dic and went away with a key toggle, I ran my scanner on it and found a few different misc things including a amplifier error, the error would not clear. so I looked it up and sure enough there is TSB for it, stating that you may have to disconnect the battery again for 5 seconds and see if the error goes away, well after 3 tries it finally cleared and all the rest went away as well and that was almost a week ago and all is well.
I have also had "security" glitches on my gmt900 and clearing the code has eliminated the issue as well.
so for shitsngiggles, give it a try and see if it works.
my k2 pickup is electrically possessed for sure, that's a different story though it often reminds me that is "alive" lol
if you do not have a very very basic little code reader they are like $30-35 at harbor freight or some auto parts stores.

 

[Doubeleive]

the main reason I say to do this though is because there may be a bad handshake between modules causing the error and resetting it can help create a fresh handshake between modules. these trucks are pretty sensitive to electrical current. Even gm states on the new T2's and newer stuff coming that wiring repairs may cause "interference" on the lan system so they recommend replacing a harness, rather than a patch job
on the k2's and up there is a "ghost in the machine", that's what happened when they decided to use more lan than physical wiring and more software, modules.

 

[gat0r]

i just have my tuner &
no codes were read & service engine also never popped up

i'll look into a dedicated code reader , in future


.... so had it towed to dealer.
mechanic looked at it for about 40 minutes & couldnt determine the issue.

he pulled a code : U0140
something about lost communication w/ BCM

he tried a reset & no joy
then he attempted to reprogram it, which resulted in new issues that he had never seen before.


<just great , lol >

anotner hour + went by, getting close to end of day..... so time to get a rental & go home, but needed charger for my phone

Serv writer escorted me back to get charger. as we get back there, mechanic started it up.
woot!


mechanic found an internal GM posting that differed slightly from what we were seeing, but similar enough for him to try it out.


overall end result: the BCM had lost its security code, but all the modules still had their original agreed upon code. so basically, BCM was talking 1 language & all other modules were talking completely diff language.

thankfully it got handled
certainly an expensive 2 days, but it's done

 

[Doubeleive]

i just have my tuner &
no codes were read & service engine also never popped up

i'll look into a dedicated code reader , in future


.... so had it towed to dealer.
mechanic looked at it for about 40 minutes & couldnt determine the issue.

he pulled a code : U0140
something about lost communication w/ BCM

he tried a reset & no joy
then he attempted to reprogram it, which resulted in new issues that he had never seen before.


<just great , lol >

anotner hour + went by, getting close to end of day..... so time to get a rental & go home, but needed charger for my phone

Serv writer escorted me back to get charger. as we get back there, mechanic started it up.
woot!


mechanic found an internal GM posting that differed slightly from what we were seeing, but similar enough for him to try it out.


overall end result: the BCM had lost its security code, but all the modules still had their original agreed upon code. so basically, BCM was talking 1 language & all other modules were talking completely diff language.

thankfully it got handled
certainly an expensive 2 days, but it's done

if you can find the TSB the mechanic found that would be helpful in case this should pop again in the future.
back on the road again