F20 N13 - 15N2 supply problem - 1B5302 error

[djoes16]

Hello, i have problem with these error. Car working but have engine error on headunit (no check engine light on dash).
 
102A01 Mass air flow sensor, signal: Electrical fault 
120408 Charging pressure control: Switch-off as consequence
122004 Blow-off valve, activation: Line disconnection
130002 VANOS solenoid valve, intake, activation: Short circuit to ground
130202 Exhaust VANOS solenoid valve, activation: Short circuit to ground
1B5302 Supply, terminal 15N_2: Short circuit to ground
1C0202 Engine oil pressure control valve, activation: Short circuit to ground
 
What i do:
- checked all wiring from sensor on 15N2 line
- changed air flow metter (MAF)
- changed integreted supply modul
- changed DME (used, maybe is damage)
 
Whats problem?
- turbo not working
- i cant make test turbo valve
- on 15N2 i have 12v but when i plug air flow metter is going down - 6.5v
- oil pressure regulator have short circut (orther new) - when i plug in in to 15N2 line, voltage going down in to 0V
 
Anyone have same problem? any suggestion?