I'll try some jumpers directly to battery for a test. And go from there.

 

​​​​​​@Zettinger Thank you very much for such a detailed DIY!! Sorry to revive such an old post, but I'm stuck and any help is very much appreciated!
I'm trying to install the mr12volt unit (https://www.mr12volt.com/products/mr...dapter-porsche) on my 04 Cayenne with CDR23 (no bose, no nav, no CD changer, but the setup for a CD changer already exists in the frunk - I have an unused fibre optic connection in the frunk and an unused power connection that has power (both these connections are covered with protective foam and are unused in the frunk)). I followed all the steps to provide power to the unit (verified that the power cables are indeed getting power, ~12.5V), and hooked the provided Fibre Optic loop between my CDR23 headunit and the mr12volt unit (I did not separate the cables as in your post because the provided loop, or Y splitter as they call it, is already wired in a directional way, so I assumed that there was no need to mess with it). When I hook the mr12volt to its power cable, a red light in the unit blinks once and then goes out and I don't see any other lights, and I can't find the unit in the list of available bluetooth devices when i search with my phone, so I'm assuming the unit is receiving power only for a split second. My question is: is this normal since I don't have the mr12volt/CDC unit programmed yet? or does my unit have a problem? I tried connecting it using only the power connection with the fibre optical cable, nothing either. Also, when I look at the fibre optical cables, I don't see any light emitted, although the loop is connected to the car's cable on one side and to the CDR23 on another side.
Could anyone please help me out? Thanks a lot!
K.

 

I'm pretty sure if you don't have Bose, Nav, or the CD changer already enabled on the PCM, that needs to be done for the Mr12V to work. The loop being there isn't enough, the PCM has to be enabled for one of the accessories that uses the MOST loop.

From the info page on the unit:

Important Compatibility note:

If the Porsche has a BOSE system, Mr12volt will work out of the box, otherwise it must have an external device, such as a CD changer, Satellite, external Navigation or Phone module in order to function. Without it one of the mentioned functions must be programmed by the dealer to activate support for Mr12Volt unit.

For CDR24 there must be a factory CD changer installed, otherwise the P600 will not function correctly.

 

Also, make sure you adjust dip switches on mr12volt to work with cdr23.

 

@sburke91 Thank you for your reply!! I had made a mistake actually. I hadn't plugged in the fibre optic loop on the cable that's in the frunk. Once I did that, the unit got power and I was able to connect my phone and to use the USB. Now to the dealership to get them to program it in for me, I hope they wouldn't make a huge deal out of this.
Thanks again!

 

I have my kit (Rennkit version) installed and can connect my phone to it over bluetooth. However the car doesn't seem to recognize it. I have a CD-24 with Bose and no CD changer. I have seen conflicting info on whether I need to have the car re-programmed to turn the CD changer setting on.

If I do need to change this setting can a Foxwell NT630 do this? Or do I have to go to the dealer.

 

I know this is an old point but I'm wondering if you ever got your mr12volt adaptor working. I have a 2006 Boxster S with the CD-24 Bose radio and no CD changer. I have the unit installed but the car doesn't recognize it and I'm hoping that having the CD changer setting turned on in the cars software will fix it. Since we have the same setup I was hoping you got your working...

Thanks, Speakerdesign

 

I’ve had a mr12vokt working flawlessly in my 2097 C2S Cab for years, in place of CD changer in loop. I now get the following error when I power up the ignition. All fuses appear ok. Any troubleshooting suggestions?

 

I observed a similar error on my 2006 C4S cab on a really hot day. So hot that I had to put the top up and turn on the A/C which I rarely do. It was intermittent and went away once the cabin cooled off a bit. Did you get this while out on a really hot day?

 

Do check the FO connections - rarely they are not perfectly aligned or jiggle out of alignment. Check for 12VDC voltage at the black connector into the module.

In general:The BTR-3 Module behaves in this way:

• Everything is well connected, with an activate FO signal to the BTR Module;
• When first powered up, red LED blinks once then stays off;
• When head unit is in any mode except CD changer mode, red LED stays off;
• When the head unit is in CD Changer mode (i.e. BTR-3 is in use), red LED stays on;
• When "Car Kit" (via Bluetooth) is paired, blue LED stays on;

 

We have a customer with the BTR-3 installed and is using an iPhone to pair. This is a CDR2 in a 2008 Cayenne with no phone module. When he makes or receives calls from his paired iPhone, the system stops streaming music, but then the caller cannot hear a voice and the caller's voice does not come through the speaker. It worked fine when he first installed the BTR-3. He bought and tried a 2nd mic, same issue. Could there be a setting on the iPhone that is trying to connect automatically to something else like Airpods? I am not an iPhone owner, so have not experienced this.

As he relates: The night I installed it, I tested making calls using the supplied microphone with both of my iPhones, knowing I’d use the system for personal and work calls at some point. The test calls worked perfectly and we’re very clear. A few weeks passed since then and I hadn’t taken any calls, but now phone calls won’t come through the system, only on speaker phone. I can be listening to Bluetooth music, take a call, and the system won’t run the microphone or audio through the car like it did when I tested it. I wanted to reach out for support or tips before I begin trying a new microphone and trying other things from there.

-I can stream music without a problem.

-I've only ever been able to receive or make a call from my phone itself. I could make a call with Siri or simply accept a call from the phone and the phone audio continued in place of BT music and the microphone picked up my voice. It was a seamless transition from music to audio, just like using a pair of Airpods or bluetooth headphones.

-Currently, receiving or making a call (via Siri), no one can hear or say anything that is audible through the system on either end. The phone is simply in regular hand-held call mode. It's as if the phone doesn't recognize the module as being the equivalent of headphones anymore. I've tried changing the settings under the bluetooth device itself from headphones to car stereo and others, but they don't allow me to select "bluetooth device" as a 3rd option in lieu of speaker phone. When going from streaming to a call, the music stops, but the phone audio no longer plays through the speakers and the microphone doesn't pick up anything. No phone or BT module settings were changed in the meantime. Message on CDR:

 

I'm also seeing the Mr12volt have a slight connectivity issue with the power/ground harness on the device. It must vibrate loose enough for it to cause errors on the PCM.

 

Hmm That might be my problem. What is the issue EXACTLY?

 

It sounds like you need to have MOST ring enabled since you don't have Bose or any MOST device operating.

 

I have that too and I learned the cause.

My 997 does not like to stay unlocked.
If I just drive off, 1 out of 10 times this happens.
It is caused by the start routine of the car, if the Mr12Volt needs a second more to start as the rest MOST devices, this will happen.

To resolve, I usually stop at a traffic light, stop car, pull key and lock the doors. Wait till I hear the PCM spin the CD drive and open again, fire up the car..

All back on track.

I got used to locking and unlocking the car when I go in the garage. When i do that, the problem never came up.