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.
Unlocking/locking the Vehicle: Notes
The vehicle unlocking/locking procedure is initiated by the following system components:
- ID transmitter
- Mechanical key/spare key
- Exterior trunk button (only unlocks the trunk)
- Central-lock button
- Interior trunk button on the A-pillar (only unlocks the trunk)
- Outside door handle *
- Central locking button * trunk.
* Vehicle equipment for Comfort Access.
The central locking system activates the following system components:
- Central locking, driver's and front passenger door
- Central locking, rear doors
- Central locking, fuel tank
- Trunk central locking system (with automatic soft-close drive).
The following example shows the signal path when the trunk is unlocked.
| Index | Explanation |
|---|---|
| 1 | ID transmitter |
| 8 | Central locking, driver's door |
| 2 | Rear window antenna |
| 9 | Central locking, fuel filler flap |
| 3 | Remote control receiver in diversity module |
| 10 | Trunk central locking system |
| 4 | Car Access System 4 (CAS 4) |
| 11 | Trunk automatic soft-close |
| 5 | Junction box electronics module (JB) |
| 12 | Footwell module |
| 6 | Relay for central locking |
| 13 | Door contacts |
| 7 | Central locking, front passenger door and rear doors |
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.