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.
Front Lumbar Support
Using lumbar support, the backrest can be individually adapted to the spinal column and thus ensures relaxed driving. Lumbar support is a standard feature in the multifunction seat.
The button for the lumbar support adjustment is located on the side of the front seat and is connected via the LIN bus to the seat module. The function of the lumbar support is integrated completely in the seat module. The lumbar support is adjustable from terminal 30B ON.
| Index | Explanation |
|---|---|
| 1 | Button for lumbar-support adjustment |
| 4 | Backrest inclination and head restraint adjustment |
| 5 | Longitudinal seat, seat-height and seat inclination adjustment |
The seat module requests the button status for the lumbar support adjustment via the LIN bus an on a cyclical basis. Lumbar support is provided by two inflatable air cushions in the backrest. The desired air cushion is inflated with air or deflated via two solenoid valves until such time that the button for the lumbar-support adjustment is released.
The pump for lumbar-support adjustment delivers the required air pressure. The pump and the solenoid valves are activated from the seat module.
The seat adjustment switches are read in from the seat module via the LIN bus.
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.