Odd Buick Enclave problem

Our 2011 Buick Enclave has been losing both FM and XM reception at the same time intermittently for the last few months, and now all the time. AM, CD, Aux, NAV all work normally. Occasionally with just the key on and engine not running, the FM and XM will come back and be crystal clear, but once the engine is started, 0-3 seconds later, the static is back and those two features are out of commission until it decides to randomly come back with just the key in the on position. But it always goes to back to all static once the engine is started.

Wondering if anyone has any suggestions on things to check? Been doing research and these Bose/Buick systems do have their share of issues, but none identical to this one. If I could be sure the issue was inside the head unit, I'd go aftermarket. But would hate to swap and have the issue persist. Thanks for any input.

Has anything been added to the vehicle like HID lights. The antenna on the vehicle handles AM/FM and XM. If AM works it's not likely the antenna. The XM is handles by a separate tuner unit and the audio is sent to the radio. It is possible something in the vehicle is powering up with the engine running and putting out interference. The only common thing is the antenna on the roof. When the XM goes out, does the radio display anything?

-------------
sparky

Thanks for the reply. No mods to the vehicle at all.

When the XM is working with the key in the acc or on position and the engine off, the display reads "XM Preview" (we dont have a current subscription) and there is demo music playing from the XM station. After the engine starts, the display reads No XM Signal when it goes all static. Does that indicate anything helpful?

I see what you're saying with possible interference from something after the engine is started. Unfortunately after the engine is turned off, the FM and XM don't always come back when the key is turned to the ACC or ON position without the engine running. It seems to take a while sitting before it comes back, but there's no pattern I can detect. Very odd.

If the radio says No XM signal then you likely have an antenna issue. The antenna on the roof handles everything and is a module so it is likely that it is at fault.

-------------
sparky

Thanks for that info. Do you know if the FM signal is also processed through the electronics in that antenna module? If so, it would make sense that unit would be the problem. I was thinking the FM antenna was just a straight through connection, like the old style antennas, but maybe not?

Just had a thought... Is the Bose factory system HD FM? If so, that would explain the FM totally going static if the circuitry in the antenna base is failing. Did some research but couldn't find out for sure.

Took a chance and swapped the antenna base unit, problem fixed. Hope this helps someone who's having similar issues.