DCC system debugging First:Don't assume it is the DCC system or loco! Check your track, make sure you have good power. Next find the LEAST COMPLEX way to reproduce the problem. If you can make it happen on rollers on an isolated track section, debug in that environment.Test with a different locoMany people test the system with a loco that has somehow gone defective. If you base the health of your system on one loco, it's usually a mistake. Try a second loco.Check the system by minimizing the variablesPut the loco right near the track feedsdisconnect other track feeddisconnect the track feeds and power a separate 3 foot section of trackuse a different throttleuse a hardwired throttlecheck your power supply voltagePacket analyzersA common issue is that you get erratic operation somewhere on the layout. Usually it is bad wiring, but occasionally it is something else.This is where attaching a packet analyzer to the rails lets you verify what you are sending is what is being received. Also, some systems just put crappy data on the rails, poor packet timing, etc.PricomPricom made a nice portable one, powered from the rails, mono LCD readable in full sun. If you find one of these for sale, buy it! There is some integration with JMRI.NCENCE also made a little module to allow looking at packets. It also seems to be discontinued. I have one, but have not played with it yet, some integration with JMRI also.Arduino - based Here's one I was pointed to: https://rudysmodelrailway.wordpress.com/2015/10/23/dcc-sniffer-packet-analyser-with-arduino/