what possible fix for p1602 passat 4 motion 2.8 engine, cranking but will not start

Question

voltage drop at fuse 31 and 32

Answer 1

P1602 Voltage supply terminal 30 too low

Battery being weak will set this code , Check for any code that is set, If there is no code whether in the pending , then you need to do the basic test, With a scan tool look into the data for the RPM, during cranking you would need more that 250 RPM in order to start, if less than inspect the CKP sensor

​Test the charging system when you set a P1602,