I just finished dealing with this problem and it cost a fair bit. At first i thought it was the CLB. I waited more than a month to get it from a retailer in Canada. I put the new one in (it already had a bypass installed) but it didn't fix the problem. I got the car towed to GM dealer who was going to order another CLB because they figured the new was was bad as well...but not after they changed the BCM at $600. When that didn't work we suggested they check the relay which was installed along with the first CLB, which was the problem and a 10 minute fix. Very frustrating.