PO171 & PO174 on 2001 BMW 330i

What causes those code to trigger? PO171 & PO174. Thanks all

2 answers
Crankcase Breather
Leaking Exhaust System
Dirty Fuel Injectors
Restricted Fuel Injectors
Insufficient Fuel Pressure
Leaking Intake Manifold
Defective Mass Air Flow (MAF) Sensor
Hi, you can find out about the p0171 and p0174 dtc's here: http://repairpal.com/OBD-II-Code-P0171-and-P0174