Im having a problem with my remote start. It goes on , but shuts off in 15 seconds. I have a Ford Explorer with a viper alarm.
Just a guess, since some disengage if signal not getting thru that motor running, to prevent starter brushes overheating, burning, etc, and you say motor starts, maybe a dirty electrical connection, like oil or something got in somewhere, interfering with that signal being received. To rule that out I guess yourself or shop, have all electrical connectors looked at for oil, dirt, oxidation, loose, etc... Simply pulling connectors and pushing back on few times might do it if that the issue. Notice if it feels tight or not. If oily dirty, maybe spray male and female parts of connector with alcohol based spray degreaser. Silicone spray has fast evaporating alcohol but the silicone may interfere with electrical connection. Also, be sure your remote button not triggered by weak spring contacting when you set it down or put in pocket as that'll act to shut off if already on. I had 1 get like that. Would park car, head in, putting remote in pocket after going in, would notice car running from inside.