2006 Dodge Charger won’t start. Just recently rebuilt engine and ran very well. Then took spark plugs out to put new ones in that just came in the mail but left some light on overnight and killed battery. Charged battery back up but now it doesn’t even make a noise besides a relay clicking once when trying to start. Red light is on on dash as well *** check engine light and basically every other light on the dash as well as a dinging sound when turning the key to start. Only code is u0100. I took another Ecu and plugged it in. It started for about 2 sec then immediately died. Did this 2 more times them same thing as before, wouldn't do anything when key was turned. Any advice on what is going on?

 

Security issue. There should be a procedure to recover from it, but, I don't know what it is.

 

any more info on this anybody?

 

Could try unlocking the drivers or passenger door twice with the key, see if that helps at all. Dodge used a lot of different recovery methods over the years....

 

So you took another random PCM and just plugged it in lol? U0100 is 'lost communication with PCM'. All you did trying another one without matching SKREEM to it was lock the PCM. That's why it kept shutting off and is now locked. I doubt you left a light on overnight that killed because these things have a timer, the CAN bus shuts off power to that accessory after a set amount of time so as to NOT run down the battery since these cars are so voltage sensitive (if the battery is shot or has bad cells it won't matter). You need to figure out what killed your battery the first time and then you need to get a properly programmed and matched PCM to your vehicle.