A medical device known as a trial neuro stimulator with a diagnostics module to determine whether the therapy lead is operational for delivering stimulation therapy to improve operation in areas such as reliability and patient comfort is disclosed. The trial neuro stimulator is typically used to test the efficacy of neuro stimulation before implanting an implantable neuro stimulator in a patient. The trial neuro stimulator has a processor, memory, system reset, telemetry module, recharge module, power management module, power source, therapy module, therapy measurement module, and diagnostics module. The diagnostics module can be a lead sensor, a software detector using therapy lead measurements from the therapy measurement module, or, a combination of both the lead sensor and software detector to detect whether the therapy lead is operational. A method for diagnosing whether a therapy lead is operational is also disclosed.