A method of power management in a system comprising a diagnostic tool and a smart phone, wherein the diagnostic tool is connected to a vehicle through a vehicle connector and power is provided by the vehicle's battery, and wherein the diagnostic tool operates in a normal power state in which the diagnostic tool is connected via a wireless connection to the smart phone and draws normal power from the vehicle battery, and a lower power state in which the diagnostic tool draws less or reduced power when disconnected from the smart phone, comprising the steps of: a) establishing a communication session between the diagnostic tool and the smart phone via a bluetooth wireless connection; a1) wherein when a command from the smart phone is received via the wireless connection within a first predetermined period of time, the diagnostic tool remains in the normal power state; and a2) wherein when the command is not received within the first predetermined period of time, then the diagnostic tool switches from the normal power state to the lower power state; and b) when the command which is received at the diagnostic tool, is a power status ping from the smart phone the following steps are carried out: c) starting, by the diagnosis tool, a timer for a predetermined period of time if the battery voltage is below a predetermined amount; d) sending, from the diagnostic tool to the smart phone, a message that the connection between the diagnostic tool and the smart phone is terminating, a vehicle battery low message, and a remaining amount of time remaining on the timer; and e) powering the diagnostic tool from the normal power state to the lower power state due to the smart phone breaking the bluetooth connection if there is time remaining (312, 314) or by the diagnosis tool thereby breaking the bluetooth connection if there is no remaining time (312, 326). a) establishing a communication session between the diagnostic tool and the smart phone via a bluetooth wireless connection; a1) wherein when a command from the smart phone is received via the wireless connection within a first predetermined period of time, the diagnostic tool remains in the normal power state; and a2) wherein when the command is not received within the first predetermined period of time, then the diagnostic tool switches from the normal power state to the lower power state; and a1) wherein when a command from the smart phone is received via the wireless connection within a first predetermined period of time, the diagnostic tool remains in the normal power state; and a2) wherein when the command is not received within the first predetermined period of time, then the diagnostic tool switches from the normal power state to the lower power state; and b) when the command which is received at the diagnostic tool, is a power status ping from the smart phone the following steps are carried out: c) starting, by the diagnosis tool, a timer for a predetermined period of time if the battery voltage is below a predetermined amount; d) sending, from the diagnostic tool to the smart phone, a message that the connection between the diagnostic tool and the smart phone is terminating, a vehicle battery low message, and a remaining amount of time remaining on the timer; and e) powering the diagnostic tool from the normal power state to the lower power state due to the smart phone breaking the bluetooth connection if there is time remaining (312, 314) or by the diagnosis tool thereby breaking the bluetooth connection if there is no remaining time (312, 326).