check engine light on 2002 impreza

Fully installed and tested a remote starter on a 2002 Subaru Impreza. Everything was fine until the check engine light came on the next day. The error code in the car computer said "Neutral position switch circuit low input." Is this possibly the fault of the starter kill relay backfeeding a ground to the starter wire? I wired the coil positive to the starter wire key side.

Did you hook up all 4 wires required for R/S?

Yes, ignition,12v,accessory, and starter (interrupted w/relay for anti-grind)

Did you tie into the Neutral Position wire at the ECU?

No