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.
Circuit/System Description
The body control module (BCM) applies voltage to the high speed GMLAN serial data wake up circuit, when the ignition key is in ACC, ON or START to enable several modules for bus communication.
Depending on option content, modules that may receive the signal are as follows:
- Drive motor generator battery control module (BECM) (RPO HP2)
- Electronic brake control module (EBCM)
- Electronic suspension control (ESC) module
- Fuel pump flow control module (FPCM)
- Power steering control module (PSCM) (RPO HP2)
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.