OEM Audio Plus Sub Amp Problems

Hey guys,
I have a 2021 Tacoma sport. Decided to go with the OEM Audio Plus Reference 500 system. Installed it. Works great. Wanted to add the stand alone sub amp so I could individually control the sub with the gain control knob.

I am having trouble getting the sub amp to turn on. I used a multimeter to test the voltage going to the power wire and I’m getting mid 13volts with the truck running. So the amp appears to be getting power, but it seems it’s not getting a signal from the head unit to turn on.

Anyone have any help here? I assume it’s a remote wire issue, but I don’t know where to start. This system is 100% plug n play. I feel confident the amps/system is hooked up correctly. I called their support and the hook up isn’t the issue.

They even had me run a wire from the power wire to the middle open plug on the green amp plug, it caused the amp to turn on. It won’t otherwise.

Help! Waiting on a call back but haven’t heard from them today. Didn’t know if anyone has had this issue. If I hook things back up without the sub amp the radio and speakers work fine.

 

When you force it on with the jumper, does it have signal/make sound?

I'm assuming since the REM terminal is N/A that amp is designed to sense signal to turn on or it gets that from the interconnect cable. If so, either that has failed or it sees no input signal. Are there any DIP switches? Did you check the blue interconnect wire for voltage?

 

I checked the blue wire coming from the original amp and it’s showing 5.89 volts. Is that number too low to power the add on sub amp? I don’t see any DIP switches.

I also checked continuity with my ground wire. It’s good.

 

Amp turn on should be 12VDC or so. That's too low.

 

Worst case scenario, could I cut that blue wire coming from the amp harness and tap into it and run a wire to a fuse linked with my ignition in my fuse box? Basically bypass the original amp as a power source? Sort of how you do regular after market remote wires. Forgive me, I’m not an audio installer expert and that may be a dumb idea lol. I just want my dang sub to work. Thanks for your help.

 

I'd be trying to figure out why it's not 12VDC first. Maybe contact OEM+ and ask them what it is supposed to be. I know they think the sub amp needs 12VDC because they had you tap the amp's power to test. Does the DSP amplifier use signal sense and generate that amp turn on voltage just for the external amplifier? Is it coming through from the harness that connects to your radio?

The only thing that's 6V is maybe the rear cam turn on, is it possible the harness is pinned wrong? IDK and that's why I build my own harnesses.

 

I assume the remote wire that turns on the sub is coming through the plug n play harness that oem+ makes for the system. There is no remote wire hook up on the original amp like with aftermarket systems. It’s all through the harness.

I’ll try them again on Monday. Was hoping to figure it out without them. Been a bit of a process getting a call back from them. Super nice once you get them. Just an expensive system to not work.

 

Yeah that's normal, but the T harness usually gets it from your radio and connects at the multiconductor connector on the dsp/amp instead of at the power terminals. Some systems, however, can activate by sensing signal and generate that amp turn on so you can use it down the chain on other amps, typically a separate subwoofer amplifier. If you knew which way OEM+ is doing it you'd have an easier time finding the cause. It could be either their unit, or an issue with the harness.

 

The oem+ tech I talked to Thursday said it was likely a signal issue, possibly with the harness being a problem. He wanted to try some other tests. I never heard back. Said he would call me on Friday. Called them and didn’t get an answer. So just wanted to see if anyone on here had this issue.

The DSP sub has a 16 pin connector coming from the main harness that plugs into the head unit. The sub also has a 8 pin connector coming from the rear sub. That’s pretty much it. The add on sub connect with the harness seen in my pics. It also has another harness that the rear sub plugs into. I can send pics of this if needed.

 

Did you ever get this solved?