Volume level erratically changing by its self

The dealership says my ASL is working but I can not tell, I always have to turn it louder.

 

I never see when the ASL is working, and your description of that behavior sounds very abnormal in my experience. I suggest having the dealer take a look.

 

ASL does not show the volume banner on the MFD. Pressing either volume button on the steering wheel does. If you weren't pressing a button on the wheel, the MFD, or turning the volume knob on the radio, then it's time for a trip to the dealer.

Tom

 

I find that if I turn the wheel erratically or suddenly (usually when someone pulls out in front of me quickly without warning), the palm of my hand will hit "mode" or "volume". It's a very subtle how my hand hits it. It took me a while to figure that out.

When I was driving a friend's car (Mazda), it was happening all the time and I couldn't figure out until the BF observed me.

 

I had the same problem on my '06 that I traded a few months ago. It happened sporadically and had nothing to do with the steering wheel controls. The volume would just come up on the MFD and lower and raise itself. The dealer was never able to reproduce the problem. Have not had any problems like this with my '08 and hopefully will not in the future.

 

I suggest liberal application of the "technical tap" to the buttons on the wheel and the volume dial. A few good strong thumps with the index finger should do it.

If it's going up AND down, I suspect the volume knob (not buttons) is to blame, if the thump doesn't do it it's time for warranty service. Good luck reproducing it at the dealership!

 

Oh, and if you don't think your ASL is working just turn it to "high" to get a stronger effect.

 

This is the second car I've had with ASL and even with the response turned to high, I've never found it very useful. I still have to turn the volume up on the interstate.

 

Most likely you will need to have the radio replaced. The steering wheel controls and wiring are a possibility, but because of the way they are designed it's more likely the volume encoder knob in the radio itself is flakey. Visit the dealer, they will most likely install a new radio no questions asked. Gotta love warranties!

 

I have the same problem in my '06. It seems to occur when the temperature is high. In my case, the problem is also accompanied by a problem where the volume knob on the head unit does not respond unless I push it in and out a few times aggressively. When the problem occurs, the volume number flickers back and forth between two adjacent numbers. This is a classic symptom of a faulty rotary encoder, which is the type of component used for the volume knob in a digitally controlled head unit. I assume this is also somehow causing the random "automatic level control" problem you andand I are experiencing, but there may also be something wrong with the steering wheel switches (or the wiring or connections to them). Since this problem has been described by multiple people, I am more likely to go with the faulty rotary encoder component as the cause.

This should be covered by the warranty. I haven't yet had the chance to take mine in for repair, but I'll post the results of that visit here.

- Doug

 

I am having the exact same problem with my 2007 Prius. I can tell you that it is NOT the ASL because I turned it OFF to make sure. AND I am sure it is NOT accidentally touching the steering wheel controls. It sometimes blasts me when I least expect it and scares me to death!! I have thought about taking it to the dealer, but it only does it when it feels like it...so if anyone has any thoughts on how to proceed, it would be great!!

 

have you wiped off your wheel recently? if moisture gets in behind the buttons, they will short-out for a small lengh of time. I've had this happen recently.

As someone else has listed... your contacts may be wearing... i'm at 100k.. mine are not worn out.

If i remember correctly, the U.S. versions do not have a functional ASL system... or maybe that was only 04 and 05 units (before the software changes)

try changing the ASL volume. Set it to 0.. and jump on the freeway.. jump back off.. change it to it's highest setting and jump back onto the freeway. You should notice a change in tone as you gain speed, or accelerate heavily.

 

I'm having this problem with my 2006 Prius, and have had it into the dealer 3 times for investigation. Because I can't give them steps that will reproduce the issue 100%, they haven't been able to reproduce it. Toyota has agreed to cover the repairs if they can ever figure out what's wrong, even if the warranty period has ended, but won't just replace the steering wheel controls or stereo.

Has anyone successfully resolved this issue?

 

@DougSlug - I have the exact symptoms you describe in your post. Additionally, sometimes when i press and hold down on the fast forward or rewind buttons to "seek" within a CD track, it skips completely to another track. I have an 07 Prius, package 6 with 32k miles. I plan on asking the dealer to check it out at my 35k service, but it seems to be intermittent. I agree, high heat seems to be when i notice it more. It's 100 degrees in LA this past week!