Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Low Speed GMLAN Serial Data Line
The low speed GMLAN serial data communication circuit on this vehicle is in a star configuration. The star has 3 splice packs, located as follows:
- The splice pack SP201 is located under the left side of the instrument panel (I/P), near the data link connector (DLC).
- The splice pack SP300 is located next by the left B-pillar.
- The splice pack SP303 is located next by the right B-pillar.
The following modules communicate on the low speed GMLAN serial data circuit:
- The splice pack SP201 attaches to:
- The instrument panel module (IPM)
- The head-up display (HUD), with UV6
- The HVAC control module
- The instrument panel cluster (IPC)
- The radio
- The steering column lock control module (SCLCM), with UA2
- The splice pack SP300 attaches to:
- The audio amplifier
- The driver door module (DDM)
- The driver door switch (DDS) is attached to DDM
- The driver position module (DPM), with A45
- The digital radio receiver (DRR), with U2K
- The inflatable restraint sensing and diagnostic module (SDM)
- The left rear door module (LRDM)
- The rear integration module (RIM)
- The remote control lock door receiver (RCDLR)
- The television (TV) module, with YK6/YK7
- The splice pack SP303 attaches to:
- The communication interface module (OnStar), with UE1
- The inflatable restraint SDM
- The passenger door module (PDM)
- The right rear door module (RRDM)
Refer to Data Communication SchematicsΒ for more information.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.