Hi...I’m picking up a 2004 Coupe (automatic) with 28k miles next week. Apparently the battery was hooked up reverse polarity and the car hasn’t started since (about 6 months). Since then the person who’s been trying to get it running replaced: battery, Relay Control Module, Pulse Module, Alternator, Fuses, high amperage fuses. The car does get power on the dash and the key fob locks/unlocks the car. Also, jumping the starter to test seems okay. No CEL light or stored codes showing with a basic scan tool.

Unfortunately the car will not crank. My research leads me to believe that either the car no longer has drive authorization or is in lockdown due to too many failed attempts at starting....which I hope is a software fix/programming PCM and/or Skreem with a DRBiii. My other thought is the Powertrain Control Module has a repairable issue (I.e., bad diode). I’m assuming since the car doesn’t attempt to crank after disconnecting the battery that the Skreem may still be okay. I will eventually replace the Skreem or buy a spare from Needswings. Disconnecting the battery doesn’t produce the three start/crank typical of a bad Skreem.

Anyways, hoping to get some guidance on what might be bad and in which order/priority should this be approached. I can get parts from another 2004 Coupe recently posted as a part out. I’m also okay with having some spare parts if needed since I also have an SRT and a Limited roadster (extra starter, alternator, RCM, body control module, ignition, etc).