Q: when testing with code reader, testing monitors, 07 comes up saying that STS failed?

Hello. I would need to know more information about the vehicle in order to give accurate information. Depending on the year, make and model of the vehicle I would be able to determine what may be going on. It is also important to get the power train codes from the computer. If you want to have this starting issue fixed, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the vehicle will not run] https://www.yourmechanic.com/services/car-is-not-starting-inspection

Hello. The message your scan tool is giving, "STS : Fail" likely signifies that the scan tool was unable to retrieve a status for that monitor. This is usually due to the scan tool being incompatible with that particular monitor. I would refer to the instruction manual to see if this may be the case. In order to be able to provide a more specified response I would require a bit more information about the vehicle, such as the make, model, and engine. An engine that fires, but then stalls right away can be caused by many different things. A few common causes are a faulty idle air control valve, fuel pump, or ignition coil. In most cases a stalling engine will provide a specific trouble code or set of codes, beginning with the letter P, that may help identify what the issue is. I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose the cause of the stalling.