Help! Stuck on accessory mode. Battery dead. Recent amplifier installations.

JRadT

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Hi, I have a '17 ex-t and redid my sound system last night with my bro and at the end encountered an issue with being stuck on accessory mode.

We installed a amplifier to my factory radio and 2 amps and subs I believe wired into the accessory wire. When I turn my car off, it says to push start 2x to turn off but nothing happens, it doesn't turn off.

I drove home and parked with the same issue and figured it will turn off eventually. My battery was dead the next morning.

Any ideas ?





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PandaXpress

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What wire did you use for the accessory wire? Is it from the back of the headunit?
Did you tap a fuse for the accessory turn on wire?
The source you tapped probably stays on when the car is off and keeping your amp on which is draining your battery?
Do you have a digital multimeter? Use that to see if there is power coming from the accessory wire when the car is off.
 
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JRadT

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Engine goes off but accessory mode stays on. Yeah, no, says press twice but it doesn't work. Still in Acc mode.
 

ryanfk7

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Do you have a cvt?
 

ryanfk7

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I'm gonna' need the makes/models and maybe a simple diagram.

I believe you'd be better off to have all the aftermarket stuff powered off of a common power source (if the total is less than 10 amps; you can do a temp connection to the cigarette lighter). I'd also run the remote signal to a source other than a wire tap from the head unit.

I'm wondering if your aftermarket amps are not set correctly re: 'sensing power' versus using the signal of the remote wire. Additionally... the head unit handles so much other duties that placing additional demands on it's power source seems to be asking for trouble, gremlins, and just plain shoulder-shrugging oddities.
 
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JRadT

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Thanks for that reply. I'll see what I can do to get that info.
 
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JRadT

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Hi all, thus far what I've figured out is that it seems the mini amplifier we've connected to the factory radio unit via the accessory wire is the issue.

I jumped my car, drove around and when I parked again and stopped the engine, the persisting accessory mode issue was present until i went ahead and disconnected the amp to see what would happen, and that allowed the normal full car system shut off.

My bro who is an electrical engineer who essentially did all the wiring and speakers installation work is puzzled by this. Given he's not a car electronics expert.

This is what he said and also the amplifier I'm using.

https://www.crutchfield.com/p_158XMS400D/Sony-XMS400D.html?tp=72998

20200623_103607.jpg
 

M16

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im positive you have a grounding issue. the amp might be putting a voltage on ground, which is screwing with the BCM, which is also responsible for the push to start system and which provides the ACC voltage to the audio unit.

please post pictures of how you have your amp grounded.

other possible causes, bad wiring or defective amp.

dont use a manual switch, you will only be hiding the problem.
 

Ocelot

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Have you confirmed that the amp(?s) is shutting down when it is supposed to?
 

ryanfk7

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The amp could be backfeeding voltage. Remove the wires from your system that you hooked up to the ACC wire and see if there’s voltage there.
 

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