2001 Infinit i30: If I have codes P0505, P1320, & P0158, what should I fix first? The IAC Valve?

Question

Could the IAC Valve be the whole problem and the other codes will go away once I replace the IAC valve?

Should the ECM be replaced at the same time as the IAC valve? My mechanic said he saw no leaks. And the car still starts -- sometimes perfect - first try, but sometimes it starts hard - it takes 2-4 cranks to get it started.

Thanks for your assistance.

Answer 1

P0505 Idle air control system malfunction

P0158 -02 sensor circuit high voltage (bank 2 sensor 2)

P1320 Malfunction in the ignition primary signal

The replacement of the IAC will result in the same situation. P1320 is the main concern with the hard starting,With a scan tool the the cranking RPM needs to be inspected with a use of a scan tool the RPM should be above 250RPM before the engine will start. There should also be no security code active. P1320 is a intermittent condition where the primary ignition is not being seen by the ECM which result in the hard starting.Diagnose the crank sensor for this condition.