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Automatic Volume Increase Not Working...

M

mva

Charter Member
Full Member
Joined
Feb 10, 2002
Messages
126
Location
Los Angeles, ?CA
Does anyone know what controls the automatic volume increasing feature (I think it kicks in when you hit 70mph or was it 50mph?) ???? I noticed radio no longer increases in volume :9:. The one change that may have done it was my swap to the caddy cluster.

Has this happened to anyone?

-mark
 
I think it increaes volume for ever 10mph over what you have it set at from zero mph.....there is a maximum volume with stock radio and well it is not too loud......

Check the little knob thingy around the volume control and make sure is set to max SVC (Speed Volume Control) or whatever it says...

HTH
 
socalAVY said:
Does anyone know what controls the automatic volume increasing feature
Click to expand...
There is "class 2 serial" data being communicated between the body control module computer and the radio. This is how the radio knows how fast you're going, it basically taps into the same data stream as the speedometer.

It increases the volume in discrete steps, at 35, 50, and 65 mph, if I recall correctly. How much it increases the volume at each of these steps is a function of the "SCV" (Speed Controlled Volume) setting, which is controlled by the ring around the volume control. Turn it all the way down (counter clockwise) and it is off: there will be no speed related increase. Then there are several steps, with the maximum increase being all the way clockwise.

The best way to test it is to set SCV to the max (clockwise) and accelerate to highway speeds. Then with the volume turned up to where you can hear it clearly, but not blasting loud, quickly slow down (make sure there is nobody behind you!) You should hear a distinct decrease in volume.

It is not as easy to hear the change when accelerating, as the engine noise tends to overpower the volume increase.

If it seems like the SCV is truly not working, it could be a loose connection. It will probably be a pain to diagnose.

Hope this helps.

-- SS
 
socalAVY said:
Does anyone know what controls the automatic volume increasing feature (I think it kicks in when you hit 70mph or was it 50mph?) ???? ?I noticed radio no longer increases in volume ?:9:. ?The one change that may have done it was my swap to the caddy cluster.

Has this happened to anyone?

-mark
Click to expand...


socalAVY,

I usually keep my SCV turned almost all the way to the right. Sometimes, I will begin to think that it's not working, but when I'm stopped at a redlight and I turn it all the way to the left, then when I reach highway speed, I have to start cranking up the volume, so then I know it's still working. SCV is one of the reasons I don't want to give up my factory head unit. I want MP3 playing capabilites, but I don't want to give up the SCV.

Roy ???
 
Roy, there are aftermarket radios that have SCV or "GAL" as the aftermarket manufacturers call it. Harman Kardon is one of them.
 
Mark, I have the caddy cluster in my AV also but have not experienced the problem you have describe. SS describe the best way to check it out. I would give that a try and see what happens.

Vetman
 
I can see no way the cluster change should affect the scv operation - if you do not have the knob turned down I would suggest you return to the dealer. Shapeshifters description is correct and yes it is difficult at best to diagnose - even the dealers are just replacing the units. Dealers dont repair their own electronics the sublet to factory approved venders.
 
SNO SLYD said:
Roy, there are aftermarket radios that have SCV or "GAL" as the aftermarket manufacturers call it. Harman Kardon is one of them.
Click to expand...
I have found that aftermarket SCV is very hit and miss, unfortunately. I purchased an Aiwa MP3 headunit for my car and was excited to see it had SCV. Unfortunately, it didn't do anything, even with everything connected properly. Of course, some stereo shops will have demo vehicles that can be tested. Too bad you couldn't fake the speed so that you could test a headunit in a store for things like this.
 
Roy said:
I want MP3 playing capabilites, but I don't want to give up the SCV.
Click to expand...
Have you investigated using the GM9-AUX PIE interface to add an aftermarket MP3 device such as a Nomad or a Kenwood eXcelon Media Keg. (I am not certain whether the Media Keg can operate as a separate unit or whether or not it requires a Kenwood headunit, but it serves as an example.)

Just trying to offer suggestions. :)
 
TexAVfan said:
I can see no way the cluster change should affect the scv operation - if you do not have the knob turned down I would suggest you return to the dealer. Shapeshifters description is correct and yes it is difficult at best to diagnose - even the dealers are just replacing the units. Dealers dont repair their own electronics the sublet to factory approved venders.
Click to expand...
While I was not given details, my dealership indicated to me that they had encountered several problems with recent vehicles requiring the headunits to be replaced. Perhaps this was one of the reasons, though it is the first I have heard of it. Maybe socalAVY will be lucky and just bumped the SCV control to off while wiping the dash. :)
 
One more point I should have made about the SCV. One of the things that make it hard to test is that it's subtle. If it's working and adjusted properly, you really shouldn't notice that it's there.

The only time you should really notice it, is if it's turned off. With SCV off, as the speed and resultant road noise increases, it will seem like the volume is being turned down, in that it will be harder to hear the radio.

The only time that I really notice it, is sometimes when braking on an exit ramp. That's about the only time that the speed will bleed off fast enough to hear the volume being adjusted.

So, keep this in mind: If it seems like the radio is always at about the right volume, it's probably working. Only be suspicious if the radio gets harder to hear as the speed goes up.

-- SS
 
One more thing....if you don't have one already....get an aftermarket muffler...or full cat-back....when you romp on the air peddle you should here the difference in a heartbeat....very significant.... ;D

Dave
 
Thanks for the help you guys! That was it. Maybe I should learn to read the owner's manual ;)

-mark
 
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