Ford Ranger P0505: Idle Air Control System - Malfunction

P0505 This OBDII code deals with the idle control system of the Ford Ranger.  It’s a generic code, which means that it has the same meaning for the Ranger as it would any other vehicle (Ranger or not).

P0505:  Idle Air Control System:  Malfunction

P0505 triggers when there is either a stuck or clogged idle control valve or a vacuum leak.  Other causes can also be involved.  Although, they aren’t as prevalent.

P0505 Symptoms:  Ford Ranger

This particular trouble code lets you know that there is something wrong with the idle air control system, but that’s about it.  The symptoms may vary.

These are the top symptoms of P0505.

• Soon, Service engine light
• It is a rough idle
• Stalling
• Low idle speed 

Ranger P0505 Causes

The most common cause of P0505 is either a vacuum leak or an issue with the idle control valve.  While replacing the idle air control valve seems like a good idea, it’s worth your time to check for a Leakage of vacuum first.

Valve to control the idle airflow

The idle air control valve’s primary job is to regulate the idle speed of your engine.  The idle air control valve regulates the engine's idle speed by controlling the amount of air that is allowed in.

You can either get the IAC valve stuck or dirty.  The IAC valve may require a replacement or cleaning may suffice.  Here’s a great You Tube video Here are some tips on cleaning an idle valve.  

You may need to replace your idle air valve if you feel it is time. Very affordable.

Vacuum Leak

While the idle air control valve is often the cause of P0505, it’s a great idea to start diagnosing it by looking for a vacuum leak.  Check the vacuum tubes surrounding the IAC.  You may need to replace the vacuum tubes around the IAC if they are cracked or dry rotted.

Leakages around the throttle body and intake manifold can cause your Ranger's code to be thrown.  Here’s a great article from Popular Mechanics on How to locate a vacuum leak.

Carbon Buildup

It is possible for carbon to build up around the IAC inlet.  The problem can be fixed by inspecting the IAC area for carbon-blocking passages.

It can cause the intake of air to be reduced if the throttle body becomes too dirty.  You can even throw P0505.  Often, when this is the case, you’ll feel the engine stall for a second before it recovers when slowing down.  

This happens because the engine can’t adjust to this problem fast enough.  It is possible to fix the problem by cleaning it from around the throttle blades.

Conclusion

You will be able to diagnose P0505 on your Ranger.  Most of the time it’s a vacuum leak or the idle air control valve.  If you feel like there’s anything that you can add, please feel free to leave a comment below.