Class 2 Serial Data Line

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Class 2 Serial Data Line
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The class 2 serial data line on this vehicle is a ring/star configuration. The BCM and PCM form the ring portion of the class 2 serial data circuit. If one of the class 2 serial data circuits to the BCM or PCM opens, communication will not be interrupted. The following modules communicate on the class 2 serial data line:

  • The body control module (BCM)
  • The driver door module (DDM)
  • The electronic brake control module (EBCM)
  • The front passenger door control module (FPDM)
  • The HVAC control module
  • The inflatable restraint sensing and diagnostic module (SDM)
  • The instrument panel cluster (IPC)
  • The liftgate control module (LGM)
  • The memory seat module-driver w/power seat
  • The memory seat module-passenger w/power seat
  • The powertrain control module (PCM)
  • The radio
  • The radio amplifier
  • The RSA/HVAC control module-rear auxiliary
  • The theft deterrent control module w/Immobilizer
  • The transfer case shift control module w/4WD
  • The vehicle communication interface module (VCIM) w/UE1

The class 2 serial data line allows a scan tool to communicate with these modules for testing purposes, checking for DTCs, and to activate/enable/disable functions. These class 2 serial data circuits are bussed together via two splice packs and a data link connector (DLC):

  • SP205 - Located behind the I/P near the headlamp switch connector.
  • SP206 - Located in the body harness near the rear of the right rear seat under the carpet.
  • DLC - connects the scan tool to the class 2 serial data circuits.

Refer to Data Link Communications Component ViewsΒ .

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