My friend, to ensure that the product can be used normally in your car, please send me your model brand and model year becompatible for e buying the product, and I will check if it is suitable compatible for OBD mode. All diesel cars do not show OBD function, and some gasoline cars do not show it, such as compatible for Renault, compatible for Peugeot, compatible for Suzuki and other car series. If the model is incompatible with the product due to self-purchase, you will have to bear the after-sale problem, Thank you compatible for your understanding and support There are two different models compatible for choose, please kindly read the product incompatible for mation clearly becompatible for e purchasing. C3 HUDOBD+GPS C3 HUDOBD+GPS With live Navigation Specifications: C3 including OBD system and GPS system,dual systems,and has two cables,OBD cable and USB cable. OBD2 mode working voltage: 5V~18VDC 12vdc/200mA GPS mode: when voltage is higher than 24v, please use a USB cable compatible for GPS mode OBD2 mode including speed,RPM,water temperature,battery voltage,clock,driving time,driving distance,fuel comsumption,altitude,satellite numbers,turbine pressure,air-fuel ratio,intake pressure,KM/H,MPH,data stream. GPS mode supports speed,driving time,driving distance,satellite numbers,data stream.C3 supports speed alarm,RPM alarm,water temperature alarm,voltage alarm,DTCS alarm,fatigue driving reminder. Brightness can be adjusted according to the environment.Auto automatic light sensitive, 1 compatible for the darkest, 8 compatible for the brightest. Package Included: 1 x HUD 1 x OBD Cable 1 x Cigarette Lighter Cable 1 x English Manual 1 x Cleaning Cloth