Hello, These are instructions from 2006 M35 Manual.. 1.Release the lock knob at the back of the Intelligent Key and remove the mechanical key 2. Insert a flat-blad screwdriver wrapped with a cloth into the slit of the corner and twist it to separate the upper part from the lower part. 3. Replace the battery with a new one. Recommended Battery: CR2025 or equivalent Caution: Do not touch the internal circuit and electric terminals as it could cause a malfunction. Thanks, Dallas,Texas

yes

use consult-III to reinitialize sensors

if the sercity light come on when you put the key in its the mobilizer i just had the same issue i had mines told to the dealer and it was fix in a week

The cam position sensor for a 2003 Infiniti M45 will cost about $30-40 for an aftermarket brand. For an OE (factory) part, your best bet is to call the Infiniti dealer for an exact quote. Theoretically it should be in that same price range, although it's not uncommon for OEM parts to be more expensive than aftermarket brands.

Electronic Throttle Control Actuator http://www.infinitihelp.com/Ownership/Common/codes3.htm

Its on the passenger side front right on top where you put your feet. There are 2 white twist knobs. Andd it pops out so dont be afraid to pull a little.