No. 1: Please make sure the Audio cable is connected to Aux input if car has Aux input.
No.2: Please check the android factory setting (code is 2018)- Aux switching mode- SET Manual, then choose the Aux in OEM radio and go back to android see if auido come out.
No.3: Please make sure the original CD is powered on.
No.4: if there is no sound still, please check the optic fiber relocation, the video guide :
No.5: Please double check the connection of android plug to original radio to make sure it is well connected.