Went out today after having my truck sit for about 10 days and it was completely dead. like.. 3 volts dead. I was able to charge it up to 12 volts but it won't start. It just clicks and the dash goes dead, but my multi meter still shows 12v like its not even tasking the battery. I wonder what the chances are that the battery is toast, but just looks good but has no CCA anymore? Radio comes on, dash comes on, then blanks out when I press the start button. It will not jump start. I had a tow service come out under warranty and they couldn't get it to do anything, so first thing tomorrow morning, its getting towed to GM to have them check it out. 2021 AT4, 17k miles.
No crank, no start after dead battery
- Thread starter paul85
- Start date
If the battery post connections are tight, yeah, it sounds like the common battery failure.
Guess you are using a dvm. If you had a battery load tester, the needle sounds like it will sink to "replace".
Wonder if the battery plates failed and touched internally and that is why the battery was dead in the first place.
Guess you are using a dvm. If you had a battery load tester, the needle sounds like it will sink to "replace".
Wonder if the battery plates failed and touched internally and that is why the battery was dead in the first place.
It was towed to GM this morning on a flatbed and we will see here in a bit what is wrong. I even tried hooking up a known good battery with jumper cables this morning and it didn't do anything. Oddly enough, there was plenty of juice to roll down the window, take the electric parking brake off, etc.
Heard from dealer. ECM was fried... somehow?? They had one on hand and put it in and are reprogramming it now and i should have it tomorrow. Can those small lithium chargers destroy an ecm? I also had a tow company out try to jump it with one of their battery packs and it didn't work either.
Got it back early today and works like it should. Battery was trickle charged all night and is still good they say. Truck runs and operates fine. If out of warranty, an ecu replacement and reprogram would have been $800.
wishywashy
Member
Something on the ECM fried and caused the battery drain. Trickle chargers would not affect the ECM.
I wondered if perhaps when we tried to charge the battery initially and put the charger into "start" mode if it overloaded the ecu, but there should be fuses or fusible links there that should stop that kind of thing from happening between the battery and ECU. I know it pumps like 16-20 amps into the battery at 15 volts for about 1 minute or two to try to give the battery enough oomph in a short period of time to start the vehicle.
wishywashy
Member
The ECM would not draw more amps than it needs. The battery can put out 600+ amps if something tries to draw that much (starter).
If you jumped it and got the cables backwards I suppose you could fry something that way.
If you jumped it and got the cables backwards I suppose you could fry something that way.
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