System Description

WARNING: This page is about a different car, the 2004 Infiniti M45. However, it is still accessible from the selected car via links, so may be relevant.

Power is supplied at all times

through 50A fusible link (letter G, located in the fuse, fusible link and relay box)
to ignition switch terminal 1

With the ignition switch in the START position, power is supplied

from ignition switch terminal 4
to park/neutral position relay terminal 7

Ground is supplied with the selector lever in the P or N position

to TCM terminal 48 through park/neutral position relay terminals 1 and 2
from body grounds E24 and E42

Then park/neutral position switch is energized and power is supplied

from park/neutral position relay terminal 6
to starter motor terminal 1

The starter motor plunger closes and provides a closed circuit between the battery and starter motor. The starter motor is grounded to the engine block. With power and ground supplied, cranking occurs and the engine starts.