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.
Input/Output Diagnostics
While in diagnostic mode, if certain BCM inputs are activated or deactivated, BCM will respond with various indicators. For example, if a door lock switch is pressed, or if door or rear compartment lid is opened or closed, BCM will flash fasten seatbelt indicator light and will sound an audible warning tone. BCM will also attempt to perform operation normally performed by that switch transition.
BCM also responds to changes in shock sensor or tamper input. Tamper input is activated by minor blows to vehicle, and shock input is activated by heavy blows to vehicle. Shock input can be activated by tapping on shock sensor located behind right rear wheelwell. If either input is activated, BCM will cause horns to chirp. BCM will also flash the fasten seatbelt indicator light and will sound an audible warning tone.
If interior light switch is activated or deactivated while BCM is in diagnostic mode, BCM will flash fasten seatbelt indicator light, sound an audible warning tone and flash courtesy lights. On vehicles equipped with Universal Theft Deterrent (UTD), at each interior light switch transition, BCM will cause courtesy lights to flash, horns to chirp and exterior lights to flash.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.