Date registered: Dec 2005
Vehicle: W211 E320 Bluetec R129 SL500 - $1300 car ........ Ford F350 6l
Location: CA Bay Area
Mentioned: 9 Post(s)
Quoted: 1068 Post(s)
RE: Range of smart key after starting
I have no direct knowledge what smart key does, but similar technologies are used in other systems.
I have add-on tire pressure monitoring system, that sends the signal to the receiver every 5 minutes, driven or not.
But when pressure drops to low, the alarm signal will go right away and be continuous for 15 hr.
So my guess is, that you are dealing with at least 2 different issues here.
1. smart key receiver allows for the signal to be "lost" for some time, before sending shut down command
2. From what other members wrote, the car will not shut the engine off till you stop, or get to very low speed.
So my guess is, that on the freeway you can go till you have to slow down for fuel stop without key presented. As long as you start with it.