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.
Movement Sensor (IMS)
The movement sensor (IMS) uses ultrasound to detect movement inside the passenger compartment. The Doppler effect principle is used to determine if the received sound wave has a different phase compared to the transmitted sound wave. Any difference in phase is interpreted as movement in the vehicle. If a movement is detected, a trigger signal is sent to the central electronic module (CEM), which triggers the alarm.
The movement sensor (IMS) is located in the headlining in the center of the vehicle. This enables it to cover the greatest about of vehicle space possible.
There are diagnostics for both movement sensors.
Use the Manual With the Right Hardware
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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.
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