I had an Astrostart 2205U installed with the alarm kit in my Subaru WRX Sti a few years ago and I have been having issues with it as of late. Since the car is a manual transmission there is the whole procedure that has to be performed prior to getting out of the car to ensure that it is set for future starts. Everything was working fine for a while and then the one day I went to remote start the car and it starts but just after the car starts the remote starter will try and start the car again while it is running like it doesn't know that it was started. I know that when the system was installed the installer had some issues with getting it to work due to the fact that the key is chipped and it has to be in the module correctly in order to send the signal to the ignition to fool it into thinking the key is in the ignition. Could the key in the module be the issue? If I have the key in the ignition with the car running and I hold in the start button and then get out of the car it will continue to run after I remove the key and exit the car so I wouldn't think that it would be the module unless it doesn't need to always send the signal to the ignition. Someone mentioned about the system possibly not seeing a high enough RPM to know that the engine is on and that it might need to be recalibrated. Anyone ever hear about anything like that and if so is there a way that I can do that or do I have to take it back to the dealer that installed it?
Sounds like the tach wire or voltage sense isn't working. Had any engine or electrical work done lately? Might have disconnected or knocked a wire off. Try to "re-learn" whichever method your remote starter is set up for.
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I haven't had any engine work done at all other than the normal oil changes, etc. Possibly the wiring under the dash? I know that the modules are mounted under there and the one tends to hang down sometimes and I have to push it back up a little. I'm not really sure how to re-learn it though.