2007 Elantra SE subwoofer install, harder than you realize. Options

[cclngthr]

Yesterday, I had my amp installed in my new 07 Elantra SE. To tell the truth, it wasn't as easy as most people would think. The new HD's have a extensive CAN line system in the BCM, where the ECU is actively monitoring everything from lights to the engine. If the BCM sees a higher voltage draw than original configuration, the ECU will tell the BCM to throw a code and either turn off the system or create a *no start* situation where the engine will not start without a scan tool reset. Resetting the ECU CANNOT BE DONE BY PULLING THE FUSE. A scan tool is required to pull codes. These cars are not mod friendly especially the electrical system. You MUST be knowlegable in computer software and hardware design to understand how it works.

I got around the BCM by not hooking the remote lead to the radio circuit. Since the radio is hooked up to the BCM and the radio's voltage is monitored by it, the extra .5-.6 volt draw created by the amp remote can cause the BCM to shut things down. The aux power circuit can have a extra draw on it because thats where extra stuff can be plugged into without causing a migrane headache.

The deck I have does not have a RCA output for an amp. However by connecting a speaker line output to a line input converter to the rear speakers, (separate from the power and ok to hook into) the audio source is now complete.

After hooking everything up to the dash circuitry, wiring the back is done with the normal routine. Amp is mounted in the usual spot.

I have the 6 speaker and ipod/aux headunit with the steering wheel controls. It looks stock, but it has a lot of thump. In the school shop, the shop walls were actually vibrating with a factory deck.

[natesi]

What's a "CAN line system" and a "BCM"?


ALSO (AND THIS IS A BIG ONE) if the comptuer is this picky, what would happen if you actually replaced the stock stereo? What if you replaced the stereo and used the remote lead off the new deck? In either case, would the car not start?!? That's got to be crazy man.

Thx,

-nate

[cclngthr]

What's a "CAN line system" and a "BCM"?
ALSO (AND THIS IS A BIG ONE) if the comptuer is this picky, what would happen if you actually replaced the stock stereo?  What if you replaced the stereo and used the remote lead off the new deck?  In either case, would the car not start?!?  That's got to be crazy man. 

Thx,

-nate

BCM= Body control module. This is hooked up (literally) to nearly all of the circuits in the car. It has a computerized CAN (controller access network) connection to the ECU. The CAN lines go to most of the various modules in the car (power window modules to switch modules to the radio.

In the older cars, (lets use a power window circuit), power goes to a switch/relay then to the the window motor. Instead of doing this, in the HD, power is not sent to the switch on the door and then to the window motor; but a low voltage signal is sent FROM the switch to the BCM, which tells the window to roll down via a high voltage circuit.

It is possible to replace the stock deck, but getting one to fit the HUGE opening is unlikely. Hooking that up to the radio circuit (which comes from the BCM) could mean that if the new radio power draw is different than the stock deck could mean that the ECU (which is connected via CAN line to the BCM) could tell the BCM to shut down some of the BCM systems. This means the radio circuit as well as other circuits could be automatically turned off to prevent damage to the systems. In a fail safe condition, engine power could be reduced in 1/2, to a complete shut-down of the motor, creating a no-start situation.

[opz]

Wow. That sucks. Glad you found a way around it though, but it sounds like a really big pain to do all that though...

[cclngthr]

Wow. That sucks. Glad you found a way around it though, but it sounds like a really big pain to do all that though...

That is how the car is designed. Since I took the service training last summer I know how to work with the BCM regarding mods. A lot of stuff that has been used throughout the years does not work on the newer cars. A lot of things have to be thought out. For me, it was easy to figure out what circuit to tap into without creating a problem. A lot of shops would just tap into the radio circuit and not realize the ECU is programmed to monitor the entire electrical system in the car. It makes it harder, but once you know how it works, you can work with it.

The HD is not mod friendly. Most cars are that way now.

[natesi]

Wouldn't it just be a lot simpler and more reliable to do it the old way? You know, wire the switch to the window motor? I mean, why make it so freaking complicated? Seems like potential point of failure, where there really doesn't need to be one. Sorry, I'm just confused. There must be something I don't get here.

[cclngthr]

Wouldn't it just be a lot simpler and more reliable to do it the old way?  You know, wire the switch to the window motor?  I mean, why make it so freaking complicated?  Seems like potential point of failure, where there really doesn't need to be one.  Sorry, I'm just confused.  There must be something I don't get here.

Not really. If you look at it this way, as the car is designed currently, all of the switch wires have a low voltage signal wire that goes to the BCM. The high, 12 volt wires are separate and the switches won't have the problem of heating up and blowing out. Although there are more wires, all of the main 12 volt leads has been reduced. It makes it safer. Also if there is an electrical problem, having the CAN system capable of shutting down selected systems prevents a lot of damage. Since there is the availability of the ECU CEL capability, finding problems is easier.

[Bobzilla]

Most manufacturers are doing/have gone to this setup. While the "easy part" of using the scan tool to find the short is better, all the control modules are a pain. That is a teething problem honduh is having right now. Constant electrical gremlins reminiscent of mid-70's german cars. Also, this means that to find a short/problem you now need the several thousand dollar scan tool for each individual manufacturer. It's the manufacturers way of making money.

[cclngthr]

Most manufacturers are doing/have gone to this setup.  While the "easy part" of using the scan tool to find the short is better, all the control modules are a pain.  That is a teething problem honduh is having right now.  Constant electrical gremlins reminiscent of mid-70's german cars.  Also, this means that to find a short/problem you now need the several thousand dollar scan tool for each individual manufacturer.  It's the manufacturers way of making money.

I know. I had to purchase an upgrade for my scan tool so I can see what my car is doing. Since the scan tool I have is the newer one, I did not have the new software yet.

[natesi]

>>It's the manufacturers way of making money.

I don't doubt that for a second! Thanks for the explanations.

This post has been edited by natesi: Nov 3 2006, 10:07 PM

[cclngthr]

Also, the stock alternator is a 135 amp unit. With a low voltage signal on a lot of the switches (3-5 volts vs 12 volts), this would also save on the power consumption. However there is more stuff on the car too. The EPS, (electronic power steering) consums 50 amps, so the car could be maxed out already.

[CyberGecco]

On hte fascia side of mounting an aftermarket h/u, there are two fascias available for the HD... one the double-din opening sized version, and one the din-and-a-half plus sized opening version seen in some of hte higher versions of the HD. While a pain, it will most likely be possible to install a din-sized aftermarket radio, physically, in that hole, and have it flush.

As for the electrical side...that, not a clue