On an operating system, a device (Insteon #2456S3 ApplianceLinc) spontaneously showed up in the device list with an ! When I removed the device and tried to reinstall it again, it gave me this: "New device errors 1E.F5.37 cannot determine Insteon Engine". I need to stress that the device did still communicate before I removed it. I could turn the device and associated programs on and off in the console. Now it will not even find to link it. Is the module recoverable or not?

The applianceLinc is a single band device. They were discontinued some time ago. "Cannot determine Insteon Engine" means that the PLM cannot communicate with the device. Either the device has failed or you have a communication issue.

You can replace it with a dual band on/off module

Click Start Linking and then Press and hold set button till it dings always works best for me for adding devices. Is that method you used or did you key in the insteon id?

It seems that the device partially failed. It actually followed the program until I removed it from the program and tried to re-register it. The only issue was the big red ! . After I removed it from the program, I tried searching by letting it find it with the link mode. When that didn't work, I tried adding it using it's address and choosing the exact description from the list. All I got back was "Cannot determine Insteon Engine" and it refused to link. When it was still working, I guess it retained some semblance of it's link structure, but that got "forgotten" when I removed it. There must be some internal address that got scrambled.

Or the 470uF/35V capacitor failed or is deteriorate. I had one start cycling on and off at about a 30 cycle rate. I replaced it and it again was fine. I did it to all my real old V1.4 modules. I have also had the 30V Zener diode in the V4.0 and above short out. Rendering it dead.

9 hours ago, gschoffstall said:

When it was still working, I guess it retained some semblance of it's link structure, but that got "forgotten" when I removed it

I've seen this with older Insteon device that have been in service for years. I could have a working virtual circuit of Insteon devices in a scene.. but if I went to add or change something in the scene, that device would always have the green 0101 next to it, meaning it would not take updates.