Something like the ScanGauge or Interceptor Scan Gauge I offer can let you monitor parameters while driving which can be very helpful in troubleshooting plus you can read and reset the Check Engine Light.

Since a 440 can easily be caused by incomplete tightening of the gas cap, it is a very common code. Resetting it by pulling the battery does not fix the problem but allows the computer not to have to complete the number of cycles needed to reset it on it's own. An easier way to reset the computer (besides using a gauge) is to remove the black plastic cover below the CD changer area and unplug the 3 colored connectors (stay away from Yellow sheathed wires as always) for a few minutes - this way saves your rado presets and clock settings.