Rear audio alert sensors not working - suggestions?

[Bikel]

My rear audio alert sensors recently just stopped working. Rear BU camera is completely functional - just the audio portion fails to sound when close to an object while backing up. Thought maybe a fuse, but then couldn't find a listing for it in the operators manual. Suggestions?

[LYKUNO]

From the owner' manual: Malfunctions in the system> If a warning tone is audible for about five seconds when you turn on the ignition, there is a malfunction in the system. Have the problem corrected by your authorized Audi dealer. Keep the sensors in the rear bumper clean and free from ice so that the acoustic park assist system can function properly.

It goes on to say this: Adjusting the warning tones
The warning tones can be adjusted in the MMI*. - Select : [CAR]> Parking system .
• Rear volume · rear sensor volume
• Rear frequency - rear sensor frequency
• In-car entertainment fader -when the parking system is switched on, the volume of the active audio source is lowered .
The newly adjusted value is briefly heard from the signal generator. The settings are automatically stored and assigned to the master key with remote control.•


I'd suggest going into the Parking system settings and maxing out the volume and perhaps changing the frequency and also checking the fader switch control's setting

[Bikel]

Thank you Lykuno. Just checked it and the MMI would not allow for me to modify any variables under parking system settings. It just kept defaulting back to level 3 no matter what volume/frequency I changed it too. I suspect maybe something more, so off to the dealer I suppose...

[LYKUNO]

Have you done a VCDS scan for errors? Perhaps doing that could reveal a faulty module or wiring issue that could be related to the lack of volume. Either way, let us know what you find out.

[Jroyalty7]

I have the same thing going on right now and it is a short to one of my sensors... as confirmed by VCDS scan. I've just been too lazy to order a new sensor and take off rear bumper.

Sent from my SM-G975U using Tapatalk

[Bikel]

I have the same thing going on right now and it is a short to one of my sensors... as confirmed by VCDS scan. I've just been too lazy to order a new sensor and take off rear bumper.

Sent from my SM-G975U using Tapatalk

Good to hear. Hoping mine shows the same for a relatively inexpensive fix. Should know more next week...

[RyanJon]

I’ve you put it in reverse and put your ear to the sensors you can hear them click, on my b6 when this happened I diagnosed this way and replaced the 1 that had stopped clicking and all is good again

[LYKUNO]

I’ve you put it in reverse and put your ear to the sensors you can hear them click, on my b6 when this happened I diagnosed this way and replaced the 1 that had stopped clicking and all is good again

Interesting, and hadn't heard or read about this until now. Here's a YT video describing the process on an Audi:



For confirmation, I just followed the process on my S4 and could definitely hear the faint ticking sound coming from each of the sensors.

[jsh139]

Alternatively, you can enable the park visualization with VCDS/Carista and it will show you exactly which sensor is malfunctioning because it will be constantly lit up.

[Bikel]

I’ve you put it in reverse and put your ear to the sensors you can hear them click, on my b6 when this happened I diagnosed this way and replaced the 1 that had stopped clicking and all is good again

Interesting, and hadn't heard or read about this until now. Here's a YT video describing the process on an Audi:



For confirmation, I just followed the process on my S4 and could definitely hear the faint ticking sound coming from each of the sensors.

Very helpful guys. I will check it out this weekend and report back. Thanks again...

[HOUs4]

My sensors also stopped working. I had a long tone for a while, then nothing. Rear cam still works. My buzzer is broken (confirmed via VCDS scan showing open or short to ground H15) and ear test on bumper sensors.

Where is the buzzer located? I've seen it may be behind the left hand rear seatbelt mechanism, but I'd rather not tear into panels just to locate.

[Bikel]

well, the ear test produced nothing. not a peep from any of the sensors. so now thinking a short somewhere else? going for a scan tomorrow, so stay tuned...

[LYKUNO]

May not be a short, could also be an open, e.g., a connector that is unplugged or not fully seated, or a fuse. Here's a diagram showing the parts involved, including the sensors, controller, control module, wire harness and the warning buzzer (part #2). Most of the components (except for the sensors) are located behind the cubby in the passenger side of the trunk. Also, for HOUs4, the warning buzzer/tone sound seems to be coming from the cubby area, above the controller bracket, possibly from the C-pillar on the passenger side. Unfortunately, the diagram doesn't show exactly where the buzzer is located, nor the cable connection to it.

[LYKUNO]

More info that may be helpful regarding HOUs4's 01543- Parking Aid Warning Chime (H15) 009- Open or Short to Ground. This thread on the A5oc forum addresses the location of the buzzer that seems to correspond with where I'm hearing the warning tone.

As the poster (plat27265) states: "The rear parking aid buzzer is located in the right passenger side panel. It seems, according to the service manual, that it is mounted in the right rear seat belt guide. You can get replacement buzzers in Ebay for cheap. All you need is sometime to remove the rear interior trim panel." See the thread.

[HOUs4]

More info that may be helpful regarding HOUs4's 01543- Parking Aid Warning Chime (H15) 009- Open or Short to Ground. This thread on the A5oc forum addresses the location of the buzzer that seems to correspond with where I'm hearing the warning tone.

As the poster (plat27265) states: "The rear parking aid buzzer is located in the right passenger side panel. It seems, according to the service manual, that it is mounted in the right rear seat belt guide. You can get replacement buzzers in Ebay for cheap. All you need is sometime to remove the rear interior trim panel." See the thread.

Thanks lykuno. There's a lot of info on a5/a6 but I wasn't able to find any specific to the s4. My replacement buzzer is on the way - I'll update when I find exactly where it is.

[LYKUNO]

Thanks lykuno. There's a lot of info on a5/a6 but I wasn't able to find any specific to the s4. My replacement buzzer is on the way - I'll update when I find exactly where it is.

Great! I'm 99% sure that the buzzer tone I hear is emanating from the upper right side of the trunk. I wish I could have spotted exactly where it's located but it does look like the right side trunk panel will need to be detached to get closer to the source of the sound. If I only had a borescope! In the meantime, I'll keep looking for better, more precise info on where that buzzer is located on the B8 S4s.

[Bikel]

Interesting, and hadn't heard or read about this until now. Here's a YT video describing the process on an Audi:



For confirmation, I just followed the process on my S4 and could definitely hear the faint ticking sound coming from each of the sensors.

So figured out it was in-fact the speaker. All fixed now. However the ticking sound test as described above did not work on the B8 for me, and still doesn't post the repair. So just FYI...

[LYKUNO]

So figured out it was in-fact the speaker. All fixed now. However the ticking sound test as described above did not work on the B8 for me, and still doesn't post the repair. So just FYI...

Good to hear you're back in business. Can you confirm the location of the speaker? Inquiring minds want to know!

[Bikel]

Good to hear you're back in business. Can you confirm the location of the speaker? Inquiring minds want to know!

on the passenger side under the rear deck lid..

[LYKUNO]

on the passenger side under the rear deck lid..

Thanks for confirming the location. One thing I forgot to ask. I understand the sensor ticking diagnostic is not working for you, but what did you mean by " ... and still doesn't post the repair."? And when you had the car scanned, what trouble code (if any), and is it still being displayed after the speaker replacement?

[Bikel]

Thanks for confirming the location. One thing I forgot to ask. I understand the sensor ticking diagnostic is not working for you, but what did you mean by " ... and still doesn't post the repair."? And when you had the car scanned, what trouble code (if any), and is it still being displayed after the speaker replacement?

The ear test did not work as described in the video before my repair, and then the same non function after the scan, repair & the code was cleared. Someone/anyone try this technique on a B8 with success? because it didn't work for me..

[LYKUNO]

Just for clarity, in your original post, you said: "My rear audio alert sensors recently just stopped working. Rear BU camera is completely functional - just the audio portion fails to sound when close to an object while backing up." So the speaker/buzzer was determined to be the problem, and was replaced. However, if the BU camera is still working as before, and the audio feature (beeping as objects are nearby while backing) is still not functioning, than nothing really got fixed. If an indy repair shop or dealer determined the speaker was bad and replaced it, since it still doesn't provide the audio warning, something else has got to be non-functional. Although a code was cleared, it would likely come back if the real problem wasn't properly repaired, and knowing the code could help us get the issue isolated and provide direction for a permanent repair. If you paid for a repair that didn't solve the issue, the shop should step up and either fix it correctly or refund what you were charged for a speaker. Of course, there could have been more issues than just a speaker, but it really sounds (no pun intended) that this wasn't a complete and satisfactory repair of your S4's problem.

[Bikel]

No. No.. I just didn't make myself clear. Everything is working properly post replacing just the interior speaker. I just could not ever duplicate the clicking sound at the sensors in the bumper like in the video. Not pre, nor post the replacement of the speaker. I am just stating for reference that the senors on the B8 might not emit the same clicking the same way that B7(?) in the video link does. Make sense?

[jsh139]

I tried to hear the clicking in my car and it wasn't consistent. Every once in a while I could hear it, and then it would go away. It was weird. I should break out a stethoscope or something.

[LYKUNO]

No. No.. I just didn't make myself clear. Everything is working properly post replacing just the interior speaker. I just could not ever duplicate the clicking sound at the sensors in the bumper like in the video. Not pre, nor post the replacement of the speaker. I am just stating for reference that the senors on the B8 might not emit the same clicking the same way that B7(?) in the video link does. Make sense?

Oh, that's good news! As long as you're hearing the beeping when backing towards an obstacle, and it changes from interrupted beeps to a solid tone as you get very close to the object, then you should be good. And as mentioned earlier, you should now be able to adjust the tones volume and frequency from the MMI:

Adjusting the warning tones
The warning tones can be adjusted in the MMI*. - Select : [CAR]> Parking system .
• Rear volume · rear sensor volume
• Rear frequency - rear sensor frequency
• In-car entertainment fader -when the parking system is switched on, the volume of the active audio source is lowered .
The newly adjusted value is briefly heard from the signal generator. The settings are automatically stored and assigned to the master key with remote control.•

While I understand you don't hear the ticking sound, my 2011 B8's sensors definitely tick when I followed the YouTube procedure above. However I had to get down on my hands and knees and place my ear directly over the sensor to actually hear the faint ticking sound with the ignition on (but not running) and the car in reverse (with the backup camera showing on the MMI screen). It's not much louder than a watch ticking IMO.

[Bikel]

Oh, that's good news! As long as you're hearing the beeping when backing towards an obstacle, and it changes from interrupted beeps to a solid tone as you get very close to the object, then you should be good. And as mentioned earlier, you should now be able to adjust the tones volume and frequency from the MMI:

Adjusting the warning tones
The warning tones can be adjusted in the MMI*. - Select : [CAR]> Parking system .
• Rear volume · rear sensor volume
• Rear frequency - rear sensor frequency
• In-car entertainment fader -when the parking system is switched on, the volume of the active audio source is lowered .
The newly adjusted value is briefly heard from the signal generator. The settings are automatically stored and assigned to the master key with remote control.•

While I understand you don't hear the ticking sound, my 2011 B8's sensors definitely tick when I followed the YouTube procedure above. However I had to get down on my hands and knees and place my ear directly over the sensor to actually hear the faint ticking sound with the ignition on (but not running) and the car in reverse (with the backup camera showing on the MMI screen). It's not much louder than a watch ticking IMO.

So i guess i might then conclude it could be time for me to get the ol' ears checked out? lol

[LYKUNO]

So i guess i might then conclude it could be time for me to get the ol' ears checked out? lol

LOL! Maybe the 2010's used an earlier design of the sensors that didn't incorporate the ticking component. Regardless, it's good to know that your beeper is now beeping!

[svt]

Any tips on replacing the speaker on a 2012 A4? I can't get the damn seat belt guide out.