Raido, seat belt and pcd sounds not working

[Dawie #3]

Hi all.. Hope you well
Re 2009 e90
The radio was working one morning then stop for 5 min a shop. Jumpes back in and the radio wont work or any any sounds

Please guide me.. The professional radio those not seem to want to work. I have no seat belt or pcd sounds

The lights on the raido lights up but wont power on.

I have check fuse as well as the fuse st the back of the radio. Seems fine

What could be wrong

 

[NBN]

It's a common problem, it's probably the head unit that is fried.

 

[Juzza93]

Hi There, Like 4 years ago LOL.

Tell me did you ever come right? What was your findings? I have the same issue.

Regards.

Justin.

 

[Dawie #3]

Hi There, Like 4 years ago LOL.

Tell me did you ever come right? What was your findings? I have the same issue.

Regards.

Justin.

Hi there no unfortunately I did not.. I tried changing the radio with a working one.. same issue.. i traced the optic cables no luck. Have you perhaps got yours working

 

[KarshS]

AI Answer:

This is a common issue on BMW E90 models and usually points to one of a few possible causes:

1. Amplifier or Audio System Failure​

• If your car has the Hi-Fi or Logic7 system, the amplifier in the trunk (usually on the left side) might have failed or lost power.
• Check if the amp is getting power and if the fuses related to the amp are intact.

2. Faulty Fuses​

• A blown fuse can cut power to the amplifier or audio system.
• Check the fuse box (behind the glove compartment and in the trunk) for any blown fuses related to the radio, amp, or PDC.

3. MOST Fiber Optic Loop Issue​

• BMW uses a fiber optic network (MOST bus) for audio components.
• If any device in the loop (amp, Bluetooth module, CD changer) fails or loses connection, the entire audio system can go silent.
• A quick test: look for a red light in the fiber optic cable when disconnected—if no light, there’s a break in the loop.

4. PDC and Audio Linked​

• Since both the radio sound and PDC tones are gone, it suggests the audio output path is dead, not just the radio.
• This strengthens the case for an amp or MOST bus issue.

5. Water Damage​

• On E90s, water ingress in the trunk can damage the amp or wiring. Check for moisture around the amp area.

---

✅ Quick Steps to Diagnose:

1. Check radio settings (make sure volume isn’t muted and sources are correct).
2. Inspect fuses for radio and amp.
3. Check the amp for power and signs of water damage.
4. Inspect fiber optic connections for light signal.
5. If you have access to a diagnostic tool (like INPA or ISTA), scan for audio system faults.

 

[Dawie #3]

AI Answer:

This is a common issue on BMW E90 models and usually points to one of a few possible causes:

1. Amplifier or Audio System Failure​

• If your car has the Hi-Fi or Logic7 system, the amplifier in the trunk (usually on the left side) might have failed or lost power.
• Check if the amp is getting power and if the fuses related to the amp are intact.

2. Faulty Fuses​

• A blown fuse can cut power to the amplifier or audio system.
• Check the fuse box (behind the glove compartment and in the trunk) for any blown fuses related to the radio, amp, or PDC.

3. MOST Fiber Optic Loop Issue​

• BMW uses a fiber optic network (MOST bus) for audio components.
• If any device in the loop (amp, Bluetooth module, CD changer) fails or loses connection, the entire audio system can go silent.
• A quick test: look for a red light in the fiber optic cable when disconnected—if no light, there’s a break in the loop.

4. PDC and Audio Linked​

• Since both the radio sound and PDC tones are gone, it suggests the audio output path is dead, not just the radio.
• This strengthens the case for an amp or MOST bus issue.

5. Water Damage​

• On E90s, water ingress in the trunk can damage the amp or wiring. Check for moisture around the amp area.

---

✅ Quick Steps to Diagnose:

1. Check radio settings (make sure volume isn’t muted and sources are correct).
2. Inspect fuses for radio and amp.
3. Check the amp for power and signs of water damage.
4. Inspect fiber optic connections for light signal.
5. If you have access to a diagnostic tool (like INPA or ISTA), scan for audio system faults.

Thanks for this info.. its helpful. My. Model did not come with am amp in the boot.
Must be an MOST issue