How does FOB work ????

Reply Subscribe

Thread Tools

Search this Thread

Oct 21, 2008 | 08:26 PM

#21

Vette_DD

Team Owner

Joined: May 2004

Posts: 82,175

Likes: 1,319

From: McKinney TX

St. Jude Donor '21-'22-'23-'24

Quote:

Originally Posted by talon90

Thanks Jim. I worked from memory. I should have looked it up.

I didn't know that about half the ones you listed were tied to it: HUD stuff & dash light dimming & last display on the DIC. As long as I've been reading & posting here, I still learn something just about every day.

Oct 21, 2008 | 08:43 PM

#22

SpryGeezer

Drifting

Joined: Apr 2007

Posts: 1,768

Likes: 19

From: ABQ NM

Thanks all for the fob tutorial.
When a fob battery is too weak to operate the start button sensor passively, how does putting the fob in the glovebox receptacle work? Does the fob operate as a passive device like a retail store RFID theft tag or is there just enough energy in the fob battery to energize the start button sensor via the glovebox receptacle?

Oct 21, 2008 | 08:56 PM

#23

talon90

Team Owner

Joined: Aug 2002

Posts: 35,617

Likes: 167

Tech Contributor

Cruise-In 11 Veteran

NCM Ambassador

St. Jude Donor '05-'06-'07-'10

Quote:

Originally Posted by SpryGeezer

The glove box receptacle becomes the power supply for the fob so the fob remains passive at that point. Placing it in the slot excites the circuitry via inductance as I recall. You can use the fob slot even if you battery is completely dead but you must leave the battery (even dead) in the fob to complete the circuit.

Oct 21, 2008 | 09:40 PM

#24

Steve Zaino

Racer

Joined: Sep 1999

Posts: 253

Likes: 0

From: Holliston MA

OK my 2 FOB stories:

1. One of my FOB's went through the washing machine and still works fine.

2. I left my FOB in my golf bag, put the golf bag in the trunk, shut the trunk, car was locked. I could not open the rear hatch or any doors eventhough the FOB was in the trunk not more than a foot away from the rear hatch button. Why was that?

Oct 21, 2008 | 10:44 PM

#25

Vette_DD

Team Owner

Joined: May 2004

Posts: 82,175

Likes: 1,319

From: McKinney TX

St. Jude Donor '21-'22-'23-'24

Quote:

Originally Posted by Steve Zaino

2. Fob-detecting antennas do not cover that area of the rear hatch. I don't know whether it was designed this way or not, but that's the way it is. Dozens of forum members have done the same thing. They just had to find a way to get into the car. The rear hatch button does not have fob detecting electronics in it. The antenna that detects the fob outside the car near the button does.

Oct 21, 2008 | 11:12 PM

#26

onehdeagle

Racer

Joined: May 2008

Posts: 263

Likes: 0

From: Sierra Vista AZ

Quote:

Originally Posted by Pocket Aces

As I was told by the head honcho of engineering: there are two little men: one in the fob and one in the car each with 2 way radios. When you are within little man radio distance and press the fob buttons the guy in the fob radios the guy in the car and tells him which levers to pull depending on the button you pushed. These guys are not related to the guy in the fridge that turns the light on and off BTW.

You nailed it!

Oct 21, 2008 | 11:34 PM

#27

bigspyke

Thread Starter

Instructor

Joined: Apr 2006

Posts: 138

Likes: 0

From: Paradise Valley AZ

Thanks guys for the explaination/s about the fob. The knowledge the posters share on this board never ceases to amaze me. Kind of like "spreading the wealth around." Sorry, couldn't resist that.

Oct 23, 2008 | 10:42 PM

#28

user051728

Le Mans Master

Joined: Oct 2005

Posts: 7,002

Likes: 2,679

Quote:

Originally Posted by talon90

A coil wrapped around the slot activates the transponder chip in the fob.

This is actually how most fobs work, even the ones you have to stick in the slot to turn on the car (Like Mercedes or Chrysler Fobs).

Many cars have the Start/Stop button removable (Mercedes and Chrysler), or a slot right next to it (like BMW). The Corvette is one of the few cars I've seen with it hidden.