viper 791vx remote issues

I have a Viper 791VX installed in an 04 Monte Carlo. The remote is a 479V. The alarm was installed about 5 years ago and has worked well up until recently. A few days ago, I needed to replace my car battery. After finishing up, the remote would not arm the alarm. I was able to successfully enter valet mode so I figured the remote just needed to be reprogrammed. However, reprogramming did not solve the problem. I had an older remote (same model- cracked LCD) laying around so I tried that but did not have any success. After googling around for a bit, I've discovered that people have had success with disconnecting the brain and reconnecting a few hours later. Not wanting to take apart my dash in 100+ heat, I just disconnected the car battery and let it sit for a few hours. Upon reconnecting the battery, the remote works again (did not need to reprogram remote at this point either). However, while all the functions work properly, the remote itself does not update and gives the out-of-range beep code for every command sent. For instance, the car will successfully arm when the lock button is pressed, but the remote's LCD will still show unlocked and the OOR beep code will be sounded. I tried both remotes I have and had the same results. The remote does show the RX icon near the top when commands are sent. It also shows the icon once every 5 seconds or so, which I assume would be the paging mode. However, the LCD is still not updated. The TX icon is display as applicable. Anyone have any ideas?

You can just unplug the antenna connector on the dash if it's not too hard to get to.  You just unplug it and plug it back in, no need to wait hours.  Sometimes those old antenna "lockup", and unplugging them takes care of it.

As far as not getting a confirmation on the remote.  You can try opening the remote up and checking the 2 connectors inside that mate the mother and daughter boards.  Theres frail solder connections that break and will give you no 2 way operation.  You can fix them with a small tipped soldering iron.

Mark Mizenko wrote: You can just unplug the antenna connector on the dash if it's not too hard to get to.  You just unplug it and plug it back in, no need to wait hours.  Sometimes those old antenna "lockup", and unplugging them takes care of it. As far as not getting a confirmation on the remote.  You can try opening the remote up and checking the 2 connectors inside that mate the mother and daughter boards.  Theres frail solder connections that break and will give you no 2 way operation.  You can fix them with a small tipped soldering iron.

Cool, I'll try disconnecting the antenna today and see how that goes. I'm having the same issue with both remotes so I don't think it's that likely to be a remote issue. That said, I popped open the older remote and had a look. The connection between the boards looked fine. I'm having a buddy bring a new-in-box remote over today and if that is behaving the same, then I think I can eliminate the remotes as the issue. Maybe the car is transmitting garbage? So the remotes are receiving something but they don't know how to interpret it?

Could just be that lockedup antenna causing it too.  Thats why I said try that first.     I've done it hundreds of times.

Just be careful unplugging that connector.  The wires get REAL brittle.  The insulation may have come off already if it's been in a long time.   Hopefully your stuff is all in good condition.   Still..... that connector can be in there tight.  And the ears on the plug arent very big.   Sometimes fingernails work better than fingertips.