start and stall problem on my 2011 Silverado

[byrdman11]

First my Silverado was running great. One day I try to start it but battery was weak. I charged battery up try to start and bam!. Start and stall just like a security problem. Things I have done to try and fix. Run two 8 gauge wires to the rear mount battery. Reflash compute. Check all codes with a tech II no code or lights. Loosen up and re tighten ground on block. Please help. I'm a gm tech and with codes and lost of comm of a compute I will be throwing parts.

[joecar]

It was running and then one day the problem showed up...?

What year/model/vehicle...?

Do you have the Service Manual (you're a GM technician, you have access to this)...?

Sounds like the BCM and ECM have not completed doing security relearn...

key-on with failed start initiates security relearn, you can abort it by turning key off (all the way), but if you don't abort it and try to re-start then the relearn is committed to proceed, you have to wait 10 mins with key on, and then repeat 2 more times (30 minutes)... or you could relearn/relink using Tech2 or possible EFILive tunetool (VATS relink) (depending on year/model).

[byrdman11]

Yes, one day it just happened but it was after a weak battery wouldnt start engine. There is no codes in the ecm or PCM. No security light on. Yes I'm a tech. You think I should do a 30min relearn anyway? I'm thinking the leak battery mess up something. But in my 35years I haven't seen this one. One time it did this I scan the truck with the techII and everything was ok. So i just was looking at things starting truck, and it would stall and all of a sudden it started up and was fine. Run for a few weeks. Like I said install new battery and still ok, so I was thinking it was ok. But it came back like I said in my first post. Please help. 2011 Silverado 1500 came stock with the 6.2 and 6 speed. Truck has a 6.0 402i 1100 rwhp and 4l80. Truck has ran like this for a year or more. Like I said please help. I've had some bad luck from with truck in the last few month. Trans first repair it. Truck sat down for 4 months get the trans upgrades. And now this.

[monkeywrenched]

Make sure it's not simple like the idle just has to b relearned. Throttle body's on these years were known to have issues so if u switch battery now idle is gone and iac is just letting it die until relearned. Easy test is hit the pedal and try to make it run if it does slowly let off until it runs on its own.

[joecar]

+1 make it relearn idle.

If it cranks for a second and then stalls, check to see if the security indicator is lit or flashing.


When the battery leaked, did it split and the batteries acid fell out...? What is under the battery (anything electrica/electronic)...?

[byrdman11]

Guys the battery was weak. Not leaking. And I can throttle it and it just rev up more on the start stall condition. It cutting off fuel for sure. Ignition no sure but I'm thinking not. Sorry again about the battery problem mixup.

[joecar]

Ah, weak... (I know what you went thru typing that on your phone... spell corrector, argghhh).

[byrdman11]

Yes it drive me crazy when I'm in a hurry. What you think about my truck?

[byrdman11]

No codes no lights. Just a start and stall condition.

[joecar]

I'm thinking it over... try doing idle relearn as monkeywrenched said above.

[byrdman11]

I can open the throttle a little during start up and it still stall. All it will do is start and stall.

[byrdman11]

I will try tonight to do a theft learn.

[byrdman11]

Guys I did a theft relearn and the truck start up great.

[joecar]

Good deal :cheers:

[byrdman11]

A little detain about the problem. If the the ecm sat a code for anything when you was starting it over and over. The truck would start up find. Most of the time codes wouldn't turn mil light on and you was ok. But if something happen and a code turn light on and you cleaned codes bam the start stall was back. Like I said cutting injectors off. Relearned theft system and it is fixed.

[joecar]

In the service manual it says that a crank with no start will initiate a theft relearn unless the key is turned off all the way...

i.e. if you try to start and it does not, and then you try again (without turning key off first) then theft relearn is now in progress (and you won't be able to start engine until it is done)... this caught my wife (luckily in my driveway).