Replace JBL ("Premium") audio system. Speed wire, reverse wire.

Hi All.

I recently bought a 2015 Tacoma which came with the "Premium" JBL audio system which I am ripping out and replacing.

I bought the PAC RP4.2-TY11 to integrate camera/steering-wheel etc. The question I have is about the analog speed signal and reverse signal. The PAC comes with two options. One option is to use the speed/reverse wires from the factory harness (if present) and the other option is to tap into the ODB connector so the PAC module can generate the speed/reverse signals itself.

Does anyone know about the factory wiring? I wonder if I need to hook into the ODB (CAN bus) or if the factory harness has these signals already?

Anyone know?

 

You shoudn't need to run to the OBD2 with your radio. However, use these two sections from page 3 of the manual to determine for sure.

 

Thanks for the reply. This is the section I'm trying to figure out before opening up the dash (if possible). Do you expect that the truck is wired for case 1? (Vehicles that have analog signals at the radio)

 

If you have a factory back-up camera and factory nav, you should fall into one of those two categories.

Either way, it will use the same harness, and no wires will need to be run to the OBDII port. Won't matter if they're analog or CAN though because the harness and brain decode it wither way.

 

Right. I just don't want to hook up both of them because then I would have two analog signal drivers on the same line which will cause distortion. If it comes through CAN to stock JBL deck then I hook up the CAN, pull the speed/reverse signals from the PAC and call it a day, but if speed/reverse are part of the harness I send those to the deck and tie off the outputs from the PAC.

I was just hoping someone already knew what I should expect.

 

You will use the outputs from the pac no matter what. It reads the analog or the CAN signal and sends that to its included outputs.

The PAC harness does all the work for you. Analog or CAN, use the pac outputs

EDIT: I feel like an idiot. I'm so used to using the RP5's for GM vehicles. I completely forgot that toyota has two sets of those connections. Sorry for dragging this out!

If you have JBL and Nav, I believe you should be using the CAN set (output from the PAC itself)

However, it is always best to double check which set of wires match up per the PAC instructions we looked at earlier. In my years as an installer, I have seen tons of stuff that "should have" been one way but weren't. Building your harness before you double check is just asking for trouble! Luckily the radio in the 2015's (and all tacomas for that matter) come out super easy, just just head out to the garage with a panel tool and a 10mm driver and the 28 pin portion of the pac harness just to make sure of which set you'll use

 

2015 Tundra with JBL/Nav uses CAN, so I'd assume tacoma's would too

 

I'll post an update here when I get some time to take a look at the harness.

 

Here to provide an update. Turns out the 2015 Tacoma with JBL audio doesn't have CAN at the head unit. I got my oscilloscope in there and discovered the speed signal is Pulse Width Modulated and the reverse is simply 0v/12v switched.

Here's a video of me driving with the oscilloscope hooked into the speed sensor wire from the factory harness.
https://www.youtube.com/watch?v=bc-9Hn8gOYk