Hello,

I have a 2013 CX-9 GT (Bose amp and navigation-ready head unit) and I am trying to replace the head unit with an Android (KLD MTCD) unit. I am having however problems driving the Bose amp. No matter what I do all I get is 2 beeps per second at maximum volume out of the amp. I tried the CAN bus adapter that came with the unit and also a PAC RP4-MZ11 with the same result. I fed the amp using the preamp outputs of the unit and also the speaker outputs through a Scosche SLC4 line-level output converter, again everything with identical results.

So my question is, does anybody know what do those loud beeps signal? A solution to the problem will be great, but knowing what the problem is would also be extremely useful. Many thanks!

 

I have been SO unhappy with the stock stereo, did you get your aftermarket unit to work with the Bose amp?

 

I was not completely unhappy with the stock head unit, but I was not thrilled about it either and I was also spoiled with having an Android unit in my previous vehicle (so I was painfully aware of what I was missing).

In any event, as a matter of fact I did manage to make my aftermarket unit work (see below) and now I am very happy with my setup. The sound quality is pretty good (subjectively better than the stock head unit) and I also have a full Android unit built in, which opens lots of possibilities including but not limited to a wide selection of good navigation apps (both on- and off-line), Torque, and a dash cam recorder.

First, the problem I was experiencing was not caused by the audio source or the CAN bus adapter. Strangely enough, the car must be turned on (and that's a full on, not just ACC) for the first time. If this is not the case then max volume beeps are all the sound that is produced by the amp. As soon as the car is turned on once the amp/head unit combination will work thereafter on ACC as well as on ON (has been doing so for the past month or so). This appears to be a "feature" of the vehicle rather than the adapter, as the same problem manifested itself with two totally different adapters (the PAC RP4-MZ11 as well as the no-name, Chinese adapter that came with the head unit).

Now, in case you find this information useful, here is my complete setup:

1. I have this head unit. Some upgraded models with 4 GB of RAM are also available, but I am not sure whether to recommend them since they come with Android 8.0 which at this time has some issues (which will surely be ironed out at some point, but they do exist at the time of writing). This is the well regarded PX5 MTCD unit, which has great community support including custom ROMs. Note that the community support is very important (so much so that I will never buy a unit which is not MTCD or MTCE) since the sellers do not offer much after-sale support. I am currently using and recommend Malaysk's ROMs (either the Marshmallow version which is pretty solid, or the cutting-edge Oreo which has some issues but is fairly usable). There are countless tweaks available, just lurk a bit on the XDA forums and you will surely find many interesting things to play with. Right now the unit is configured almost fully to my taste. There are some glitches but they are not show stoppers; about the only thing that I have left to fix is the flaky connection with my OBD adapter (which may be caused by the adapter instead of the head unit).

2. The unit comes with a CAN bus adapter which will probably work out of the box, but has some limitations most notably the inability to set the clock. I ended up using a PAC RP4-MZ11 adapter instead, which works pretty well when the head unit selector is set on position 7 ("other"). There are however two SWC keys that are not distinguished by the adapter (not a big deal for me but worth mentioning). I did not set up double button presses at the adapter level, preferring to set up such kind of combinations on the head unit side. I fed the preamp outputs of the head unit into the adapter (which is to say, directly into the Bose amp) and that works well. The SLC4 adapter I mentioned in my earlier post is not needed.

3. To maintain the factory backup camera you need an AX-MAZCAM-6V adapter. Be careful when you purchase this as the AX-MAZCAM-6V consists of two adapters that are also sold individually: the AX-MAZCAM (for the actual wiring between the camera and the head unit) and the AX-CAM6V (for providing 6V to the camera). You need both, the AX-MAZCAM (without the -6V suffix) will not be enough. The factory camera is so-so in quality but in the end usable so I cannot recommend the obvious alternative of foregoing it altogether and install an aftermarket camera; the rewiring is not necessarily difficult, but it is a tedious job with cables routed through plenty of tight spots with plenty of opportunities for hurting one's fingers, and all of this for very little improvement in quality.

4. To maintain the USB port from the glove box you can use the AX-MAZUSB adapter. Crutchfield claims that it does not work on Bose-equipped CX-9s, but in my case it actually works as advertised. I found no way to maintain the 2.5mm glove box jack short of a complete rewiring (which I did not try, as I have no use for that input).

5. For the dash cam recorder I purchased an inexpensive camera from eBay. I do not remember the actual link but it looks like this one. Basically any UVC camera will probably work (the UVC driver is included in all the Android versions running on these units as far as I know); just find one with a reasonably wide angle.

The wiring of all of the above is rather tedious but overall just a matter of following the directions that come with the different adapters. If you decide to use the RP4-MZ11 you will need to remove the stock vehicle plug and solder the one that comes with the RP4-MZ11 in its place as per the instructions that come with it. If you decide to use the stock CAN bus adapter you will have to pay attention to the audio outputs to the amp. The default seems to be to have speaker-level signal on them (since the head unit cam be used without an external amplifier), though that might be replaced by line level signal when the "with amplifier" option is selected in the factory settings of the head unit. I am not sure about that since I used the RP4-MZ11 which provides convenient RCA plugs that fit nicely in the preamp outputs of the head unit, which sidesteps the amp in the head unit altogether in all circumstances). According to the documentation I gathered from various places the Bose amp is supposed to be happy with line level or speaker level signal, but again I have not tested this.

You will end up with a pretty big ball of wires and at least one box (the CAN bus adapter) behind the head unit, so you will have to be careful when tucking all of them in (it might take some time but it is possible). I stuck the dash cam on the windshield just adjacently to the rear view mirror and I routed the cable as follows: I routed the cable underneath the trim on top of the windshield, then I fished it underneath the top of the A pillar cover, and then hid it underneath the weatherstripping around the door until I got it low enough to route it underneath the dash. I used the passenger side for this circuit because I also have a USB hub placed in the glove box, but the driver side will probably work as well. The length of the cable was just enough to mate it with the USB cable from the head unit. I placed the GPS antenna near the front-center speaker (under the center cover that is removed for installing the head unit) and secured it with some double sided 3M tape (the antenna itself is magnetic, but I could not find any convenient metal surface in the vicinity); I made sure that the antenna has a clear view of the sky (plastic and glass being OK, metal not so much).

The whole job was done in about half a day (plus countless hours trying to debug the loud beeps but missing a stupid simple solution...).

Overall I am very happy with the setup. I should note however that my experience is limited to a single vehicle (2013 Mazda CX-9 GT with Bose audio) and may or may not work in other contexts so your mileage may vary. I hope that this description is useful and reasonably detailed, but if more details are needed do not hesitate to ask.

Cheers and good luck!

 

@bruda

Don't even know if you'll get a notification of this 6 years down the line, but I'm hoping you can help. I've just gone to install an aftermarket unit in my bose amp 2012 CX-9. I've had exactly the same problem as you. I've used an AERPRO harness, and AERPRO themselves have said I've installed everything correctly. In my case when you turn the ignition to ACC there is no alarm sound, and the unit actually works great, but when you turn it to ON or START it goes off.

Can you explain exactly what you did to fix it? If I can't get it to work do you think replacing the Bose amp with an aftermarket amp would work? I've tried a cheap Eonon head unit and an AERPRO one and both have the same issue.

TIA

 

Hi,

I completely forgot that I even have an account for this forum, but amazingly enough I did receive the notification. The CX-9 continues to be my daily driver even, and in the meantime I changed the head unit once to a more modern Android unit of the same kind, which turned out to be pin compatible with the rest of the gear so it was a plug and play affair. The loud beeps did not happen again so I am guessing that the security system (or whatever it is) detects the adapter rather than the head unit (which makes sense since the adapter is the one that talks on the CAN bus). This is all to say that I do not remember clearly my first attempts since it's been 6 years and I have not touched that system since. Anyway, to answer your questions (as much as I can):

(A) The only fix to your issue that I can recall goes like this:

1. Plug the stock head unit back in. Start the car. Verify that the Bose amp works with the stock head unit.
2. Stop the car, unplug the stock head unit, and set up your new head unit.
3. Start the car, or at least switch ignition to ON. Do not go to ACC first, go directly to START or ON (that was as far as I remember the crucial step to make the Bose amp happy).

To the best of my recollection the above steps got my setup working and it has been working fine ever since.

(B) My educated guess is that changing the amp will also solve the problem, but I cannot guarantee that; it is possible (but very unlikely) that some handshake on the CAN bus will still happen. Note that Bose is notorious for using strange speakers (with very low impedance) so you may also need to replace the speakers (but I have not checked if this is the case with this vehicle).

Sorry for not being able to be more precise, it's been a long time. I hope this helps. Good luck.

 

Mate thank you so much for replying! I'm gonna give it a go tonight when I'm back from work. Do you remember whether you actually had to disconnect the battery before setting up the new unit? Or whether you just turned the car off?

 

It may be worth trying if all else fails but I never disconnected the battery during my fight with the amp. I did blow the fuse once (which is more or less equivalent to a however involuntary battery disconnection ) but that happened at a different time (years later).

 

For anyone still searching for a fix. Here's my response to a user in another forum https://mazdas247.com/forum/t/alarm-...ose.123874140/

Long and short, after a ridiculous amount of attempts at other fixes, I got the amp replaced and it now works perfectly.