How the keyless entry works in the 2003-2006 Tahoes

MAY03LT

Original poster
Member
Nov 18, 2011
3,420
Delmarva
Keyless Entry System Description and Operation
The keyless entry system is a supplementary vehicle entry device. Radio frequencies or discharged batteries may disable the system.
Keyless entry can operate the following components:
  • The door locks
  • The interior lamps
  • The parking lamps
  • The headlamps
  • The puddle lamps (if equipped)
  • The horn
The keyless entry system has the following main components:
  • The transmitters
  • The passenger door module (PDM)
The PDM communicates with the body control module (BCM) through the keyless entry serial data circuit. When you press a button on a transmitter, the transmitter sends a signal to the PDM. The PDM sends a request to the BCM and the BCM performs the appropriate function.

Unlock Button
Press the UNLOCK button once in order to perform the following functions:
  • Unlock the driver door only.
  • Illuminate interior lamps for a predetermined amount of time or until the ignition is turned to the RUN position with a valid key.
  • Illuminate the puddle lamps (if equipped) for a predetermined amount of time or until the ignition switch is turned to the RUN position with a valid key.
  • Disarm the content theft deterrent (CTD) system (if equipped).
  • Deactivate the CTD system when in the Alarm Mode (if equipped).
Unlock All Doors (Second Operation)
Press the UNLOCK button a second time within 3 seconds of the first press in order to perform the following functions:
  • Unlock all doors.
  • Flash the parking lamps twice.
Lock All Doors
Pressing the lock button will:
  • Lock all of the doors.
  • Turn the interior lamps on for 2 seconds.
  • Turn the puddle lamps on (if equipped) for 2 seconds.
  • Arm the content theft deterrent (CTD) system (if equipped).
Press the LOCK button again within 3 seconds of the first press in order to perform the following functions:
  • Chirp the horn.
  • Turn the interior lamps on for 2 seconds.
  • Turn the puddle lamps on (if equipped) for 2 seconds.
Panic Alarm
Important
On some export vehicles the panic alarm will not reset after a predetermined amount of time. The panic alarm must be manually turned OFF using one of the methods listed below.
A single press of the transmitter panic button will:
  • Pulses the horn.
  • Illuminates the interior lamps.
  • Flash the parking lamps.
  • Flash the headlamps .
  • Turn the puddle lamps on (if equipped).
All of the above will occur for a predetermined amount of time or until:
  • The Panic button on the transmitter is pressed again.
  • The vehicle is unlocked with the key.
  • The ignition switch is turned to the RUN position with a valid key
Keyless Entry Personalization
Personalization of the remote activation verification is only available on select vehicles equipped with either a Driver Information Center or a Secondary Information Center.

Rolling Code
The keyless entry system uses rolling code technology. Rolling code technology prevents anyone from recording the message sent from the transmitter and using the message in order to gain entry to the vehicle. The term "rolling code" refers to the way that the keyless entry system sends and receives the signals. The transmitter sends the signal in a different order each time. The transmitter and the PDM are synchronized to the appropriate order. If a programmed transmitter sends a signal that is not in the order that the PDM expects, then the transmitter is out of synchronization. This occurs after 256 presses of any transmitter button when it is out of range of the vehicle.
I'm getting together some info for my Tahoes remote start install and came across this for how the keyless system works in those trucks. Instead of the LGM receiving the RKE signal like the TB/EVs the PDM (passenger door module) does.
 

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