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.
System functions
When the seat belt is fastened (door closed), the control unit for the electrically motorized reel on the left (EMALI control unit) or the control unit for the electrically motorized reel on the right (EMARE control unit) activates the drive once over a certain period of time. With the help of the electric motor, the seatbelt strap is rolled up, thus removing the belt slack.
In critical driving situations or in the event of a possible accident, the control unit also activates the drive. The duration is set in such a way that the drive is activated by the control unit until a collision occurs or until a critical driving situation ends.
To calculate whether there is a critical driving situation (e.g. vehicle oversteering), the two control units (EMALI control unit and EMARE control unit) use the data from the following systems:
- Integrated Chassis Management (ICM)
The ICM control unit provides the systems in the entire vehicle with the dynamic driving state in the form of signals (e.g. data such as lateral and longitudinal acceleration, yaw velocity).
- Dynamic Stability Control (DSC)
The DSC control unit delivers information such as the speed and brake pressure.
- Crash safety module (ACSM stands for "Advanced Crash Safety Module")
The crash safety module sends a message with the status of the seat belt buckle contacts.
| Index | Explanation |
|---|---|
| 1 | Dynamic Stability Control (DSC) |
| 2 | Central gateway module (ZGM) |
| 3 | Crash Safety Module (ACSM) |
| 4 | Car Access System (CAS) |
| 5 | Power distributor in junction box |
| 6 | Control unit for electrically motorized reel on the right (EMARE) |
| 7 | Drive for right-hand electrically motorized reel |
| 8 | Rear power distribution box |
| 9 | Drive for left-hand electrically motorized reel |
| 10 | Control unit for electrically motorized reel on the left (EMALI) |
| 11 | Integrated chassis management (ICM) |
| FlexRay | Sub-bus |
| Terminal 15 WUP | Wake-up line (terminal 15 wake up) |
| Terminal 30 | Terminal 30 permanent positive |
| Terminal 30B | Terminal 30B, base operation |
| Terminal 31L | Terminal 31L, load earth |
| PT-CAN | Powertrain CAN |
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.