Opened but unused. This product's OBD2 mode is not compatible with all hybrid vehicles, electric vehicles, trucks, light trucks, minivans, diesel vehicles, pickup trucks, MPVs, RVs, caravans, and large vehicles. Also, the OBD2 mode of this product is not compatible with all vehicle models released before September 2010. 【Please Read Carefully】If you experience compatibility issues with the OBD2 mode after receiving the product for the vehicles mentioned above, the customer is responsible for round-trip shipping costs for returns or exchanges, excluding defective products. Please understand this beforehand. 【Please Read Carefully】When using for the first time or switching modes, you must select the corresponding mode within 5 seconds of starting the device. Setting method (GPS mode): After connecting with the USB power cable, start the car's engine, and within 5 seconds, turn the dial key to the left once (no need to hold it down). When [GPS] appears on the screen, the GPS mode is activated. If you do not set it within 5 seconds, it will automatically enter OBD2 mode. 【Please Read Carefully】GPS mode requires the use of a USB power cord, and OBD2 mode requires the use of an OBD2 power cord. If the OBD2 mode is not supported, the engine speed/water temperature will not be displayed, and the power may turn off or restart. In this case, switch to GPS mode by replacing the cable with a USB cable. 【Abundant Display and Warning Functions】Displays supported in GPS mode: Speed, voltage, number of satellites, altitude, direction display, latitude/longitude display, and clock data can be displayed. Please note that engine speed and water temperature cannot be displayed in GPS mode. Displays supported in OBD2 mode: Speed, voltage, engine speed, water temperature, number of satellites, direction display, clock, and other data can be displayed. Both modes also have a warning function that sounds an alarm when the set number is exceeded.