P1604 Startability Malfunction
A lot of thing could cause this engine code!
-Battery
-Starting system
-Low quality fuel
-Injector compensation code
-Fuel filter
-Cylinder compression pressure
-Injector assembly
-Engine coolant temperature sensor
-Glow system
-Supply pump assembly
-Common rail assembly
-ECM
-Stop and start system
-MAP
-MAF
-Intake Air
-Coolant Temp
-Battery Voltage
-Starter Signal
-Engine Speed of Cyl #1 (to #4)
-Immobiliser Communication
-Target Common Rail Pressure
-Fuel Press
-Target Pump SCV Current
-Injection Feedback Val #1 (to #4)
-Injection Volume
-Actual Throttle Position
-Throttle Motor Duty
-Target EGR Pos.
-Actual EGR Valve Pos.
-EGR Close Lrn. Status
-EGR Close Lrn. Val.
you forgot to mention your city for guidance to a reasonable workshop.