Anyone run into a problem with the audio, including onstar and the HDD, whistling while the engine is running. IT's the same noise from the old days, remember bad chassis grounds and resistor plug wires? Anyway, dealer tore the car apart today to install a 'filter' on the amplifier (under the back seat?), but the problem is still there.

Any thoughts?

Thanks!
Mike

Mike,

Is this alternator whine (pitch increases proportional to engine speed) or is the frequency fairly stable which would indicate the interference is coming from one of the processors or from the data bus.

Mike, I hear the whistling sound you describe (changes pitch with changes in engine rpm) from the audio system in my CTS4 whenever I make or receive a call using OnStar hands-free calling. I've yet to hear the noise when using the HDD or any other sound source (AM/FM/CD/AUX).
Being that it only happens (on my car) when OnStar hands-free calling is activated, I have attributed the problem to an issue of improper/insufficient cable shielding with respect to the in-car microphone that comes with the OnStar application. I don't use OnStar hands-free calling very often, so it's not too much of a bother for me at the moment.
With OnStar equipment now included on most GM product these days, you can bet they've de-contented ('cheapened') & standardized the application to the point where the microphone and associated cabling & equipment are very inexpensive to apply to all vehicles - whether the application is to a Chevy or a Cadillac.
If the audio whistling problem you are experiencing persists, I would recommend that you press your dealer into completely qualifying the entire OnStar system - including the microphone and all associated cabling.
As a side note... the electronics and micro-processors in modern-day vehicles (whether they be automobiles, aircraft or locomotives) demand that all cable forms/harnesses be 'categorized', and that certain categories of cable form be separated from others (by a minimum distance of 1/2") to prevent interference and cross-talk. The issue in your CTS may be that one particularly sensitive cable form was placed too close to another during vehicle manufacture.
In my field (diesel-electric locomotive manufacture & qualification), we use dozens (hundreds) of spacers on each locomotive in routing & securing differentiating cable forms/categories to prevent this sort of problem.
Sorry for the rambling. Hey, I was obviously in the mood to write!
Anyway, good luck with the issue. Please let us know if/when the problem is resolved, along with any detail you may have with respect to the corrective action taken.
Regards,
RAB (Richard)

Mike,
I also have the CTS4, but have not noticed any interference of any kind. I use the On-Star hands free calling quite regularly and have found found no extraneous sounds of any kind from the phone or the audio. It sounds like it might be a random thing, but I would think that a good tech should be able to pinpoint the problem.
Good luck and keep us posted.

It is definitely proportional to the engine revs. It is most noticable with Onstar in use, but I have heard it while listening to HDD, XM and FM, though not as noticable. I told the service guy to get out his sandpaper and cleanup the chassis connections.:)

to RAB:

Who do you work with? I was at EMD in McCook for a while back in the 70s.

mike

to RAB:

Who do you work with? I was at EMD in McCook for a while back in the 70s.

mike

Hey Mike,

You worked at EMD in the 70's for a while? Small world.
I've been working for EMD since 1984. I've always been based out of the EMD facility in London, Ontario, which is now EMD's flagship plant for locomotive manufacture. I've pretty much traveled the world over the last 24 years providing technical/engineering support to our international customers. FYI.. General Motors sold off Electro-Motive Division (EMD) in April 2005, therefore I am no longer a GM employee. :ill: I had 21 years with GM.
EMD's HQ & engine plant are still in LaGrange, IL. I've visited LaGrange (Chicago) dozens of times over the years in connection with my work. Chicago is a great place to visit.

What do you do now? Do you still live in Illinois?

Richard

RAB - did you find a friend at GM to give you a discount when you purchased your CTS?

RAB - did you find a friend at GM to give you a discount when you purchased your CTS?

NOT ON MY WATCH - Hey, thanks for asking! Actually, one of the terms of the sale was that employees (such as myself) who were entitled to the GM vehicle discount at the time of the sale would retain their discount privileges for a period of 3 years. So yes, I did enjoy a discount when I purchased (leased) my CTS on Oct. 1, 2007. The eligibility for discount is scheduled to go away for us on April 1, 2008... unless of course GM decide to extend it further. We'll see what happens.

That's cool that they took care of the employees on that particular issue.

I got hit in the layoffs in '79 and decided it was time for college. Ended up in Florida, where is is a little less cold.

Great times, though. young, single and making big money for the day.