Background: 2007 911s Cabrio, Bose PCM.
Installed a Dension 500S BT:
. Followed recommendation re: unswitched power, and used the passenger footwell outlet as a source (tapped into its source power, that is)
. Followed recommendation to install as the last piece in the MOST optical loop
. Installed the unit behind the PCM, and the controller in the glove box
. Followed recommendation to have a dealer program with the PIWIS per the instructions provided by Eric from BumperPlugs
. Upgraded firmware to 0052 then 0054
. Very clean installation

It works about 1 in every 3 starts of the car. Bluetooth works with iPhone 5, audio and phone. Reading MP3s from a USB stick works.

What does not work:

1. Connecting an iPhone5 to the USB port using a lightning-USB cable. Tried multiple cables, OEM and original, without success. The iPhone continuously switches between bluetooth and direct USB, and if bluetooth is disabled, the iPhone stops playing the audio every 10 seconds
2. Every three starts of the car, the entire system crashes during the start. The engineers at Dension suspect a handshake issue. I rerouted the power supply, and tapped into the PCM power source. Same problem. When it crashes, the blue LED of the controller is OFF. Hitting the reset button on the controller and recycling power on the PCM may or may not restart the system.
Another way to restart the system is to cut power from the PCM (removing the fuse from the fuse box and putting it back for a couple of seconds).
. When the system is not working, the navigation and any audio do not work. Cannot navigate nor listen to FM or anything.

Needless to say, the engineers at Dension are at a loss. Kudos to Eric from BumperPlugs for trying very hard to help. But after 3 months of continuous disappointments, and after spending about 15-20 hours dismounting the side panels and the PCM, and remounting everything (5 or 6 trials to date), and with the only consolation from Eric that this system works 99%, just not in my case apparently, I am afraid to recommend the following:

--- stay away from Dension 500S BT ---

Sunk approximately $600 in this to no avail. At no time did Eric or any of Dension's engineer suggested to exchange the unit, in case the unit has a timing issue or a hardware issue. The same two problems that occur on day are still occurring after so many permutations and changes.

Looking for other ideas to test, or maybe, for those who decided to completely replace the PCM, how do you change the clock in the car after removing the PCM? There are some convenience features that can only be accessed from PCM...

Thanks all.. this is a great forum, I learned so much. This is my first porsche, I hope that I'll be able to contribute with my experiences in the future.

Nadim

 

I have the same problem, although for me it's 3 in every 4 starts. I turn the car on, hear a 'ticking' sound that seems like the handshake repeatedly restarting and then find a message on the PCM stating the everything in the ring is disconnected.

If I remove power to the Dension and restart, it works. If I reset the Dension then power cycle the car it sometimes works.

It's not a power issue (iPhone charges off the USB port even when the Dension hasn't initialized/the blue light isn't on). It's the last device in the loop and I'm on the right firmware. I've tried with the phone module decoded and coded. No dice.

I'd be happy to eat my words if I could figure out what's wrong, but I'm sick of learning contortionist techniques in my footwell and am on the verge of pulling it all out. Will reseat the cables one last time...

One thing I will try is to disable the Bluetooth/Phone via dip switch 6 and leave it for a while. At least I could isolate it to one aspect of the Dension not functioning.

 

NZSkater

It appears that you and I have the same exact symptoms. The clicking sound is very telling.

Could you answer the following two questions please:
. What is the model of your car and PCM
. Have you tried turning the PCM off before turning off the car (so that when the car starts, the PCM is still off), and does it make a difference in the rate of occurrence of the issue?

Also, if you pull it out, what else are you considering?

BTW, my car is a 2007 997s cabrio, based in Florida.
Nadim

 

I have the same problem going on with mine. I've tried installing it as the last device in the loop and also the first, but didn't make a difference. I also have mine powered from the outlet in the passenger footwell, but I've also tried a different power source just to rule that out. I've exchanged many emails with Dension but nothing they suggest ever improves anything. I also have a PIWIS computer and have tried many different settings in the PCM.

If I put the key in the ignition the blue light on the Dension will come on for just a second and then turns off. This causes the PCM to not be able to connect to the other devices in the loop. Then a message will come up on the screen saying that the amp and nav are not available. If I push the reset button on the Dension while the PCM is looking for devices then it will work.

I have noticed that there is some difference between just putting the key in the ignition, and turning the key to the on position. It will work normally more times by turning the key to on than by just putting the key in and not turning it.

It seems like the problem is that the Dension is not always recognizing the signal from the PCM telling it to wake up. I'm not giving up yet, but my patience with it is running pretty thin.

 

On your first point, about connecting your iphone to the USB using a lightning cable. This is a known limitation of the 500. You must use their 30-pin cable with an adapter for the iphone 5+.

 

Oh wow... Eric never mentioned it. Interesting. I will test your statement. Hopefully this will knock down one issue.

The major one is still the handshake: any idea RS4Jay where should I continue investigating ?

 

Spudster, I will try you routine: putting the key, waiting for handshake, then starting the car. Initially, I thought that opening the convertible top while the PCM is booting was the issue. I ruled that one out, plus many complaints on the web are from Coupe owners.

I also found out that turning the PCM off before shutting down the car improves the odds of waking up properly upon the start of the car. It appeared as if the PCM, when turned ON manually, had a better chance communicating with the Dension.

I am now speculating that the issue is the following (assuming that the handshake really happens during the first power on, as suggested by Dension's engineers):
. When the car is turned off, the Dension goes to "sleep", while monitoring the traffic on the MOST
. When the PCM wakes up, the Dension is trying to wake up (hence the relay clicking sound that we hear), and not able to wake up. The LED stays OFF.
. Reseting the Dension (Using the reset switch on the controller), then turning ON the PCM seems to work every time

The clicking sound seems to be the internal power relay, needed to power the rest of the Dension gateway. The continuous clicking is suggesting that it keeps trying to wake up, without success. There is a possibility that the timing on the relay is very tight, and the boot time of the Dension is either not predictable enough, sometimes falling outside of the range, forcing the boot procedure to restart. Or that the boot loader of the Dension has a firmware issue, and it crashes.

The circus about changing the power supply (which I did twice), and connecting it at the beginning of the MOST loop and trying at the end, which I did, is appalling. Takes lot of time, and how many times has this shenanigans been successful to fix this issue ?

Dension's has an engineering issue, and they are refusing to debug it properly, blaming it on the 1% of users with problems (according to their stat, the system worked for 99% of their customers).

 

We are trying our best to help you resolve this issue, and you know we are working with Dension directly so you don't have to setup a ticket on their site and wait days for an answer.

They are also puzzled, but very few customers have had issues related to these same problems. Most iPhone users never connect via cable anyway - always by Bluetooth - so the cable issue was not relevant for most.

I will continue to do everything I can to assist between Dension Engineering and you, and hope we can resolve quickly. Dension is not neglecting their responsibility and is working to try to duplicate the issues to debug. Often hard to do with US vs Euro phones/head units.

 

Eric,
We appreciate your personal commitment. As you have mentioned in other threads, once this works, I will be the first to shout it on the roofs and on the forums.
In the interim, while i appreciate the personal attention that I am receiving (assuming I am the "you" in the last quoted sentence above), the issue of handshake, which renders the ENTIRE audio and navigation system inoperable, and not only the bluetooth streaming or anything, is impacting other users as well.

If the issue was an intermittent crash of the unit rendering the bluetooth inoperable, many of us could have lived with it. The unit does not fallback into a safe mode (like a bypass mode) when it crashes, for example. And the aggravating part is the debugging sequence that many of us had to go through, that is time consuming, and sometimes expensive, while the main issue of the crash/handshake is not being properly investigated.

It would be nice for the Dension engineers to ask for technical tests I should do: maybe send me a small optical loop recorder, to record the booting sequence, and shipping back the logs and recorder to them? You may want to consider stop advising customers to switch power or position in the loop, or CDC changer programer and such, when the issue described is similar to the one you can read here.

Nadim

 

Yeah there was actually a notice about the cable issue on Dension's site. Not sure if it's still there or not.

I've installed several of these on various cars and would offer the following advice:
1. Check the DIP switches again and make sure they match the PCM 2 settings in the Dension setup guide.
2. Make sure your fiber connections are solid. Actually slide the insert out of the outer plug and make sure the fiber is seated properly. This is a common problem.
3. Make sure you have the power for the Dension connected to the switched power on key insert/exit, NOT the ignition accessory position. This is the primary cause I see for issues with Dension and NAV-TV products. Porsche's MOST bus powers on with key insert so you want the Dension to power up at the same time or you will have handshake issues.

 

1. I will do it once more, just to be sure
2. They are, I checked multiple times
3. I initially connected to the passenger footwell (unswitched). Eric suggested that I connect it to the PCM power source (unswtiched too). I did. The only benefit of connecting to the PCM power source ? Resetting the PCM fuse restarts both PCM and Dension

 

Second thought on that: while Dension recommends unswitched power (footwell, PCM source, frunk or direct to the fuse box), you are actually suggesting the opposite: a SWITCHED source ... Wow... that could work, forcing the Dension to reboot and re-start the handshake every time.

Thank's for this tip. I will try it. Do you know a source switched on key insert/exit for a 997 2007 , by any chance ?

Thanks !!!!

 

I think most of us that have this problem have already tried the most common suggestions multiple times. Making sure cables are not kinked and are inserted properly, making sure the power source is good, checking dip switches, etc. None of that seems to make a difference. It's got to be a problem with the Dension not reading the signal from the PCM telling it to wake up. I've been dealing with this for 3-4 months myself. Dension has been releasing regular firmware updates which I do every time hoping it will fix the problem, but I'm surprised they can't find a fix to address this.

 

Spudster, among the gazillions permutations that you have tried, have you ever tried the one above from RS4Jay, regarding using a "SWITCHED" source on key insert/exit? That's my next on the list (and maybe my last, sick of opening and closing these panels)... I am waiting to hear back from RS4Jay about a suggestion of where to pull power from a switched source in a 997.

If you have tried it before, can you please comment ? Thanks

 

I don't think I have tried switched power since the Dension instructions and even their tech support tell me to make sure that it's plugged into an unswitched source. I guess it's worth a try. I just need to figure out which fuse to use.