Intermittent Tach Signal Present Before Start

I bought a 2004 Saturn Ion a few years ago with an Astrostart 903 series remote car starter. I hadn't been using the starter until recently as I needed a new remote. I recently purchased a new one and programming was successful. I continue to have the same intermittent problem I had a few years ago when I quit using it. About half the time when I go to start it, the accessories flash on, but starter doesn't engage and they turn right off. The error code according to LED flash sequence is "tachometer signal already present at start attempt." Sometimes it will start on a second or third try if I turn the car on and off or retry remote starting. Nothing seems to predictably correct it. I followed the grn/blk tach wire to the ignition control module where it was connected via a wire tap connector. The wire doesn't feel loose and appears intact to the remote starter. Any help or suggestions are appreciated! Thank you

Throw away any wire tap connectors, absolute garbage and solder.