[vinnylv]

I have a small problem, but it's just getting me curious. The variable speed feature for the radio doesn't function, so I asked that it be taken care of at my next service. The tech checked it out, couldn't find the problem and spoke to VW. They told him to change the whole radio. Went in this week, they put in the new radio, (I watched him unpack it) and the feature still does not function. They said I'd have to bring it in and let them troubleshoot with the engineers.

I really don't want to leave it there for such a small thing, but I'm curious if anyone else has had this problem and how was it resolved??

 

[TREGinginCO]

Haven't heard of this problem before.


I have a question for you. Have you adjusted the Speed Volume option from 'O' to whatever level you're looking for?

 

[vinnylv]

Yes, and even checked with the tech that I was uderstanding the adjustment. He did the same with the new radio, and found the same thing---it made no difference!!!

Small thing, but perplexing. :confused2:

 

[4x4s]

It sounds to me like your radio isn't getting the speed signal properly, so it doesn't know to adust the volume. This signal is provided on the CAN-BUS.

Are there any other quirks exhibited that might be speed signal dependent? For example, do the rain sensing wipers speed up in constant rain as you go faster? If so, it may be a control module problem with the module that provides the speed signal.

 

[vinnylv]

Good thought, but they do function. The wipers will speed up as the rain increases and, it appears, when I speed up. Also, the wipers virtually stop if I stop for a light, for instance.

I think you're onto something though. The signal from the CAN BUS may be derailed to the radio only. Wish I'd have asked before going in---might have given them an area to check!

 

[4x4s]

Good thought, but they do function. The wipers will speed up as the rain increases and, it appears, when I speed up. Also, the wipers virtually stop if I stop for a light, for instance.

I think you're onto something though. The signal from the CAN BUS may be derailed to the radio only. Wish I'd have asked before going in---might have given them an area to check!

Except that there are other functions that come across the CAN-BUS, besides speed input. Steering wheel radio controls, station/track selection out of the radio to the MFI, etc. If these things function, then the CAN-BUS must be connected. That's why I was suspecting the speed signal source. In any case, a CAN-BUS problem should show on the service techs diagnostic tool scan. I would hope the tech ran the diagnostics...

 

[vinnylv]

He said he did the first time, AND spoke to VW, thqt's when they told him to change the unit.

All of the other functions mentioned work fine.

Thanks for the thoughts, though.