I have a 05 Malibu new style with a 3.5. The engine gave so I myself replaced the motor. It started and ran several times but then it got to where it would start and immediately die. It does have anti theft but it's not indicating it on the dash or scanner. The car has had electrical issue prior to me owning it. They replaced starters and alternators quite often. FYI this car was given to me is the only reason I have it. I would have never paid for it for sure. Late 2022 the fuseable link that goes from the alternator to the starter burned in half. So I fixed that with one off of a Malibu at the junk yard. Fixed the problem. Then the fuse box either shorted out or something went bad in it. So I replaced the fuse box. When I ran the codes it was saying the ECM, TCM @ BCM was not receiving signal. I've talked to a few people and they say it's a ground problem. Finding it will be the hard part. I myself will be honest am not a electrical person. I made sure all the grounds was where they was supposed to and all sensors are plugged in correctly. I need help like yesterday. Has anyone had this issue with their Malibu's?

 

Welcome from Florida. Good Luck!! Electrical problems are easy to fix but hard to find!