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.
RSE Circuit Diagram
| Index | Explanation |
|---|---|
| 1 | Central gateway module (ZGM) |
| 2 | Car Information Computer (CIC) |
| 4 | Infrared transmitter, right |
| 5 | Rear display (FD2) with rear display control unit (SG-FD2) |
| 6 | Fuse |
| 7 | Video switch (VSW) |
| 8 | Aerial diversity module with aerial amplifier |
| 9 | Rear seat entertainment control unit (RSE) |
| 10 | Rear display (FD) with rear display control unit (SG-FD) |
| 11 | Infrared transmitter, left |
| 12 | Car Access System 4 (CAS4) |
| KL.30B | Terminal 30 basic operation |
| KL.58G | Signal, footwell module light (FRM 3) |
| FBAS | FBAS signal |
| IR | Infrared signal |
| K-CAN | Body CAN |
| K-CAN2 | Body CAN2 |
| LVDS | Low voltage differential signal |
| MOST | Media Oriented System Transport |
MOST Signals at RSE Control Unit
| In/Out | Signal | Source/sink | Function |
|---|---|---|---|
| In | Control signals | FBD antenna > Antenna diversity module > CAS4 > ZGM > |
RSE control (entertainment source, track selection, etc.) |
| In | Date, time | Instrument cluster> | Display in FD and FD2 |
| In | RSE release | iDrive controller > CIC > |
Access rights |
| In | Terminal status | > CAS4 > ZGM > |
Activation conditions |
| Out | Control signals | > FD and FD2 > Display |
ON/OFF, setting |
K-CAN Signals at SG-FD and SG-FD2
| In/Out | Signal | Source/sink | Function |
|---|---|---|---|
| In | RSE status | RSE > ZGM > | RSE standby |
| In | FD and FD2 status | ZGM > RSE > | FD and FD2 standby |
The FD and FD2 rear displays each have their own control unit. The SG-FD and SG-FD2 control units are connected to the K-CAN. The rear displays are connected via LVDS to the RSE control unit. All video information is transmitted via the LVDS link. The rear displays receive the ON/OFF signal from the RSE control unit. The ZGM places the MOST signal on the K-CAN and is sent to the rear displays.
During audio playback through the vehicle's speaker system, the RSE control unit routes the audio signal via the MOST to the head unit CIC or the Top-HiFi amplifier.
Programming, coding and diagnosis of the rear seat entertainment system (6FG) take place via MOST.
| Index | Explanation |
|---|---|
| 1 | Remote control |
| 2 | Rear window with antenna, remote control services (FBD) |
| 3 | Antenna diversity module with antenna amplifier |
| 4 | Car access module 4 (CAS4) |
| 5 | Central gateway module (ZGM) |
| 6 | Rear seat entertainment control unit (RSE) |
The commands entered by means of the remote control are transmitted by radio waves.
The same frequency is also used for the radio remote control key. The frequency used is dependent on the national variant and therefore relevant for coding. The commands are received by the FBD antenna and routed via the antenna diversity module to the CAS4.
The CAS4 converts the signals into K-CAN2 messages and routes the signals to the ZGM. The ZGM places the signals on the MOST-bus. The RSE control unit receives the signals via the MOST.
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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.