Calling 112 on your cell phone will (in some parts of the world, primarily Europe) connect you to local emergency services, even if you are outside your provider's service area (i.e., even if you are not authorized to relay signals through the cell tower that handles your call), and many cell phones allow the user to place 112 calls even if the phone lacks a SIM card or its keypad is locked. However, the 112 number does not have (as is sometimes claimed) special properties that enable callers to use it in areas where all cellular signals are blocked (or otherwise unavailable).
Cars with remote keyless entry (RKE) systems cannot be unlocked by relaying a key fob transmitter signal via a cellular telephone. RKE systems and cell phones utilize different types of signals and transmit them at different frequencies.
The claim that pressing the sequence *3370# will unleash "hidden battery power" in a cell phone seems to be a misunderstanding of an option available on some brands of cell phone (such as Nokia) for Half Rate Codec, which provides about 30% more talk time on a battery charge at the expense of lower sound quality. However, this option is enabled by pressing the sequence *#4720# — the sequence *3370# actually enables Enhanced Full Rate Codec, which provides better sound quality at the expense of shorter battery life.
Entering the sequence *#06# into a cell phone may display a 15-digit identification string, but that function only works with some types of cell phones, and the efficacy of reporting the ID number to a cellular service provider to head off unauthorized use of a lost or stolen phone is limited.
Some business outfits such as (800) FREE-411 do provide free directory assistance services to cell phone customers. However, users should note that the service is "free" in the sense that FREE-411 provides directory information to callers at no charge, but cellular service providers may still assess charges related to placing such calls.