: "No XM Signal" - 2003 Seville STS

05-28-08, 12:07 AM
I have an XM radio with a "No XM Signal" problem. I posted this to the Seville/Eldo Forum with no luck. I have the Factory NAV System. This seems to happen more when it's cold outside than when warm (e.g. winter vs summer). 2003 Seville STS.

When I fire up the car, sometimes the XM radio does not come on. It displays "No XM Signal". Sometimes it takes a few seconds, sometimes 20 minutes, before it comes back on. When this happens, sometimes it flips to Channel 1 (looks like it's reauthenticating), most of the time it does not revert to Channel 1 - it's like the antenna disappeared and then someone reconnected the antenna. Surfing around to other channels reveals no other channels are working.

- When it does not revert to channel 1 (stays on the same channel I was last listening to), it can take upwards of 15 to 20 minutes for XM to resume play. After that, the last channel I was listening to starts playing. Sometimes it happens within a minute. FM, AM, WX, CD all work normally during the XM outage. During this whole XM outage, "No XM Signal" is displayed. This condition happens about 90% of the time when the problem occurs.

- When it reverts to channel 1 after firing up the car, the change to Channel 1 happens pretty much right away. I can hear some low-volume chirps and then XM works fine a bit later. When this happens (the channel 1 reversion thing), I get XM radio back very shortly. Sometimes it says, "Loading XM" and then comes back on rather quickly. This condition happens about 10% of the time when the "No XM Signal" problem occurs.

This occurs ONLY after the car has been shut off. Doesn't have to sit overnight. 99% of the time my car is parked in my garage overnight, but I can usually get the XM signal even while parked in my garage 95% of the time.

This problem also happens when the car is parked in an open parking lot with no obstructions to the Southern sky.

Sometimes togging the power (via the regular radio power knob) several dozen times seems to make it come back, but this might be a Red Herring.

Car is still under factory warranty. Dealer (a good one) can't find the problem because they can't duplicate it (seems to always be the case!). This unit (the NAV system) is the 3rd one for this car. Replacements were for different reasons. This has happened for all three of them. So, I don't think it's the head unit.

I suspect a loose antenna connection, but I don't know what the dealer has looked at, tightened, refitted, etc.

Where does the XM radio antenna cable go to? I understand that the receiver is located someplace in the back of the car, so I assume that the antenna cable goes to that.

Maybe I can start re-seating the antenna connections?

This problem is really annoying, but doesn't happen TOO often.


05-31-08, 12:03 PM
Any codes?

It sounds like the XM module - or "digital radio receiver" in GM speak" - is defective. XM usually on defaults to channel 1 (and 247) when XM isn't paid for, so if your XM account is good, I suspect the XM module is bad.

I think located LH trunk compartment on your vehicle. It's a quick changeout, but it needs to be programmed with a Tech 2 to get rid of the "Theftlock Active" message.

Replacing the nav head unit for this problem won't help.

I doubt it's the antenna, and I'm sure the dealer checked it out on the Tech2 - should read around 15-65 mA. Besides, a bad antenna usually doesn't default to channel 1.

06-02-08, 11:47 AM
Thanks, I'll call the dealer and talk to them about it. It's over there for a final look-over before it goes out of warranty.

06-13-08, 12:10 AM
Unfortunately, they were not able to duplicate the problem and they couldn't find anything wrong. Arrrgh.

Oh well.

Thanks for your help.