[Smallblock454]

Thanks for the idea.

The car isn't in sleep mode. If the car wouldn't be in sleep mode after 2 days, the key fob wouldn't be recognized at all.

But the key fobs are both recognized. They now only work from very low distance. The fobs are OK - measured the range - everything is fine. If you put the replacement alarm ecu in another car, you have the same problem. So something in that car seems to make the alarm ecu receiver to "die" / insensitive after approx 2 days. As the alarm ecu in this car has a separate antenna input, i for sure measured the antenna against ground, to test if there is a short. But there isn't. And i couldn't find any other anomalies.

I don't think 2 new alarm ecus have the same defect from the factory.