Sound & Audio Troubleshooting
For Audi CarPlay & Android Auto Retrofit Kits
SKU: BA-AUDI_MMIA38V | BA-AUDI_MMI5 | BA-AUDI_MMI4
Common Symptoms
- No sound from CarPlay/Android Auto
- Calls work but media doesn’t
- Distorted / laggy sound
- Car information or OEM chimes missing
Step 1 – Audio Mode Selection
Your Audi retrofit can work in two audio modes:
- Default Mode – AUX
- Audio is routed through the car’s AUX input.
- Select AUX in the Audi MMI → Media menu.
- Ensure AUX volume is set correctly (recommended level: 10).
- This mode gives the most stable sound quality, and all features (CarPlay, Android Auto, mirroring, AirPlay) work.
- Optional Mode – Use Car’s Bluetooth Channel
⚠️ Note: This only applies to vehicles with OEM Bluetooth Audio Streaming (A2DP).
* In the retrofit **Setup Menu → System Settings**, set **Use Car’s BT Channel = ON**.
* System will reboot.
* Pair your phone with both:
* The **MMI Box Bluetooth** (required for CarPlay/AA to launch).
* The **OEM Audi Bluetooth** (shown as “Audi MMI” in your phone’s list).
* CarPlay/AA will display as normal, but audio now routes via the car’s original Bluetooth system.**Limitations of OEM BT Mode:**
* Screen mirroring, AirPlay and wired video do not work in this mode.
* There may be a **slight audio delay** compared to AUX.
* If your Audi does not support OEM Bluetooth Audio Streaming, you **must** use AUX mode.
Step 2 – Troubleshooting Sound
| Problem | Likely Cause | Solution |
|---|---|---|
| No sound at all | AUX not selected, or OEM BT doesn’t support A2DP | Select AUX in MMI menu, or switch back from OEM BT mode |
| CarPlay launches but silent | Phone only paired to MMI Box, not OEM BT | Pair to both MMI Box + OEM Audi BT when using OEM BT mode |
| Calls work but media doesn’t | OEM BT limited to “phone only” | Enable media audio in phone’s BT settings, or use AUX |
| Sound is laggy / out of sync | Using OEM BT channel | Switch back to AUX for stable sound |
| Chimes / car sounds missing | Fibre optic loop not seated in harness | Re-seat MOST fibre loop into retrofit harness |
Step 3 – System Reset
- If changes don’t take effect, disconnect CAN Power for 10 seconds.
- Reboot the system and re-test audio mode.
Support Checklist
If sound still doesn’t work, send to 📧 support@bavarian-automotive.co.uk:
- Your order number
- Car model/year
- Audio mode you are using (AUX / OEM BT)
- Photos of wiring and toggle switch settings
- Video showing the issue
Oct 3, 2025