2003 Mini Cooper Base, Automatic CVTFACTORY OEM SERVICE PROCEDURE

Inertia Switch

In the event of an impact registering at greater than 14G the Inertia Switch goes open. This open removes the voltage from X254 pin 21 at the BC1(J3 54-pin Natural connector). The trigger of the inertia switch causes the BC1 to unlock doors.

Fig 1: Identifying Central Lock Circuit Diagram
G04724474Courtesy of BMW OF NORTH AMERICA, INC.
Factory Service Tools

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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.

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