Turning Steering Wheel Reboots Head Unit

Installed an aftermarket head unit a few months ago in our 2012. Recently, the car has been causing the head unit to reboot when you turn the steering wheel a certain amount. Like when turning left or right, not just adjusting heading or driving on a curved section of road. The head unit will be playing music just fine, then it turns off and does its reboot routine, just like when you start the engine.

I understand these cars have some kind of electric power steering. Is the PS system on the same circuit as the radio? Any other thoughts as to what might be going on?
 
What kind of interface did you use to wire it into the car?

We have a Kenwood DDX8706S stereo in the MZ5, and the first interface that I used in ours was the PAC RP4-MZ11, and it worked perfectly for about a year, but the stereo started resetting every time you turned on the high beams.

I swapped that interface out for an iDataLink Maestro RR, which I also use in my CX-5 (also a Kenwood DDX), and so far, no issues at all.
 
Coincidentally, I also used the PAC RP4-MZ11. Hmm.

That Maestro looks pricey though. Any other options? Anyone got experience with the Metra Axxess ASWC-1?
 
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I've used PAC, Crux, Metra, and iDataLink stuff. iDataLink is more expensive for a reason.

If you don't want the Maestro RR, or maybe your head unit really isn't made for it (and if it's not, then honestly there's no point in spending that much money!), go for the iDataLink Maestro SW. That's the one I run in my Silverado, and it's 1/3rd the cost compared to the Maestro RR.
 
Unfortunately, the SW doesn't seem to list the Boss BV755B head unit I have. :(

I wonder, could I just unplug the connector from the PAC RP4-MZ11 and not have steering wheel controls?
 
Unfortunately, the SW doesn't seem to list the Boss BV755B head unit I have. :(

I wonder, could I just unplug the connector from the PAC RP4-MZ11 and not have steering wheel controls?
Canbus is also used to display information on the led screen (next to the clock), so, disconnecting will disable this functionality too.
Maybe you need a different canbus adapter?
 
Maybe you need a different canbus adapter?

That's exactly what we're talking about here: the PAC vs Maestro RR.

The other brands like Maestro SW, Crux and Metra are simply steering wheel control adapters, they don't actually talk to the car.
 
Unfortunately, the SW doesn't seem to list the Boss BV755B head unit I have. :(

I wonder, could I just unplug the connector from the PAC RP4-MZ11 and not have steering wheel controls?
Dude! The Maestro SW does indeed work with your radio!
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If you asked Crutchfield, they may not have listed it. I don't know why, but when it comes to the iDataLink stuff, they really aren't the most reliable source of information. You really need to go the manufacturer's website instead.

For example, Crutchfield doesn't list the Maestro SW as compatible with my Chevy. I assure you, it is. They don't list the Maestro RR's as compatible with either of my Mazda's. Yet there they are, singing happily away! I even sent an email to Crutchfield to get on the ball. They said they were going to talk to their tech advisors, try to get the most current info up on their website.
 
Oh man, sorry I got your radio wrong! You may want to shoot them an email and ask about the compatibility. Every other Boss radio seems to be listed!

No, there's no pre-made T-Harness for Mazda, you have to manually wire the Maestro. It's only like 6 wires total though, and two of them go the the OBD-II port. But if your head unit isn't specifically made to support the RR, then getting the RR is pointless.

See that black square connector? That's made for the RR. Without that port, the RR won't do the special stuff it's capable of doing.
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Ah. That looks like a big fat nope:
View attachment 310919
So the dash information display won't work?
I think it's possible to make it work. I'd probably do more research https://www.amazon.com/dp/ (commissions earned)in the reviews/comments section. According to BOSS website, they have "SWC compatible" units and, I guess, not compatible ones.
Check the documentation of your stereo, whether it's "SWC compatible" If yes, then you might be able to build the harness which will support canbus information exchange.

Edit:

I think it's possible to make it work right, according to the documentation found here, see page 7 and page 14. Both ways to use the steering wheel control are available on your stereo.

Which steering wheel control do you have? Do you use just the harness or the harness + canbus box?

In any case, what I would do if I were you, I'd pull out the harness going into the stereo, take a multimeter and measure the resistance between two wires going into SWC jack or between "1N and 1T" or "1P and 1T".

I'm just thinking out loud here: if you're using the "no canbus box" mode, then, each button is identified by the resistance between "1N and 1T" or "1P and 1T" see here.
Turn the wheel, see what happens. If the resistance drops to zero, then it might be that the 1N is shorted to the ground somewhere, causing the reboot. I'm pretty sure that 1N/1P to GND should never be zero. Could it be the problem with the clock spring then?
A quick fix here would be adding a small resistance to 1N or 1P and re-train the buttons, according to page 14.
See schematics, I tried my best.


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Following up on this. I pulled the dash top to access the RP4-MZ11 to see if something was wrong with it (I'd just stuck the box on top of the head unit so that's all the disassembly I needed to do to access it). I managed somehow to pull the box off the harness plug, and there wasn't enough slack to reconnect it easily so I pulled a little more of the harness out from behind the head unit. After plugging it in, I started the car and racked the wheel full left and right, and the head unit worked properly—no cutting out or rebooting! Maybe the harness had gotten pinched or something, IDK. But for now I'm not gonna look a gift horse in the mouth.
 
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