I performed a KOER test and got these codes can any one tell me if these are related to the idle air control? Any help will be greatly appreciated.

 

Ford 3-digit codes seen here: https://therangerstation.com/tech_li...gitcodes.shtml

538 means you initiated a "test sequence" and didn't press down on the gas pedal when you should have, thats the "goose test", so ignore it

Ford uses an IAC(idle air control) Valve on the upper intake manifold, next to throttle

411 means computer was trying to lower idle RPMs with IAC Valve and couldn't lower RPMs enough to set its "target idle" RPMs
Computer was programmed at the factory to set specific Idle RPMs based on coolant/engine temperatures, cold engine needs higher idle, warm engine lower idle RPMs

411- "Idle speed system(IAC) not controlling idle properly (generally idle too high)"

It could be IAC Valve problem but vacuum leak would be more common, IAC Valve lets more air in to raise RPMs, vacuum leak does the same thing but not "controlled"

Do this test
Start cold engine
let it idle and unplug 2 wire connector on IAC Valve, engine should stumble and maybe stall, this means IAC Valve is working at least for cold idle

Warm up engine, for at least 5 minutes
let it idle
Unplug the 2 wire connector on IAC Valve, idle should drop to 500 rpms, barely running, or may stall, either is good it means no vacuum leaks
If idle does NOT drop then there is a leak.

Start with PCV hose and PCV Valve, PCV Valve should be changed every 3 or 4 oil changes or every 2 years, if it sticks open at idle it acts like a vacuum leak.


You can remove IAC Valve, 2 bolts
Plug in its 2 wire connector and turn key on
IAC Valve should be open fully with key on engine off
Watch the valve inside and unplug the 2 wire connector
Valve should close with no power
Plug wires back in and it should open again
Repeat as you see fit

it only moves 3/8" so not much, but DOES move if its working OK

 

Thank you very much that information is greatly appreciated and I will try what you suggested.