b6 sat radio now says"no signal"

[jupiterfish]

2005 b6 s4 avant factory nav & bose w/ original xm module

my xm factory equipped oem symphony II radio was replaced about 2 yrs ago with a new unit due to cd skipping. today i went to hookup my once working XM radio (had a previous subscription) and the new radio displays "no signal" i had the dealer chase the connections and they stated that everything is connected correctly.

should i replace the old control module first (assuming its bad) before replacing the antenna they (dealer) suggested (from an non-electrical testing approach) for $700 ?

is there anything else i can check on my own?

i have factory navi and it works fine (uses same connected sharkfin).

how can i test my signal for the xm?

thanks....i would hate to drop $700 for something that is a simple solution.

[naiku]

What's the part number on your XM tuner? I don't think they all work with the RNS-E. If it originally worked with your Symphony II, and now does not work with the RNS-E it may be the wrong tuner. It looks like you need either Sirius 8E0 057 593D or XM Part No. 8E0 057 593E. I also don't know if you need to use VAG-COM to enable XM with the RNS-E.

[jupiterfish]

sorry i meant i have a new symphony II not an rns-e. could it be a vagcom issue with the radio antenna not being programmed?

the stations show up but still displays no signal. is there a cheap antenna i can plug in the back to test if the signal strength is low or the sharkfin antenna needs to be replaced?