Jeep Cherokee Cherokee P0505 - Idle Air Control System - Malfunction

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

P0505:  Idle Air Control System:  Malfunction

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

P0505 Symptoms:  Jeep Cherokee

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.

Below are some symptoms that P0505 is most commonly seen:

• Soon, Service engine light
• Don't be rough
• Stalling
• Very high idle speed 

Cherokee Causes P0505

P0505 can usually be caused either by 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 for Idle Air Control

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 How to clean an idle air control valve  

They are available if you decide that an idle valve control valve is needed. 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.  Examine the vacuum tubes near the IAC.  You may need to replace the vacuum tubes around the IAC if they are cracked or dry rotted.

You can code your Cherokee by leaking around the throttle bodies and intake manifolds.  Here’s a great article from Popular Mechanics on How to locate a vacuum leak.

Carbon Buildup

It is possible for carbon to buildup in the IAC intake area.  The problem can be fixed by inspecting the IAC area for carbon-blockage passages.

It can cause the intake of air to be reduced if the throttle body becomes too dirty.  This can cause P0505 to be thrown.  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.  This problem is usually solved by cleaning the area around the throttle blades.

Conclusion

You will be able to diagnose P0505 on your Cherokee.  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.