Jeep Grand Cherokee Idle Air Control System - Malfunction

P0505 An OBDII Code that addresses the idle air control system within the Jeep Grand Cherokee.  It’s a generic code, which means that it has the same meaning for the Grand Cherokee as it would any other vehicle (Grand Cherokee or not).

P0505:  Idle Air Control System:  Malfunction

P0505 usually occurs due to a stuck idle valve or a clogged idle valve.  However, there are other possible causes.  Although, they aren’t as prevalent.

P0505 Jeep Grand Cherokee


Índice de Contenido
  1. P0505 Symptoms:  Jeep Grand Cherokee
  2. Grand Cherokee Causes P0505
    1. Valve for Idle Air Control
    2. Vacuum Leak
    3. Carbon Buildup
  3. Conclusion

P0505 Symptoms:  Jeep Grand Cherokee

This particular trouble code lets you know that there is something wrong with the idle air control system, but that’s about it.  These symptoms could be different.

Below are some symptoms that P0505 is most commonly seen:

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


Grand 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.

Jeep Grand Cherokee P0505 Diagnosis

Valve for Idle Air Control

The idle air control valve’s primary job is to regulate the idle speed of your engine.  This is done by making sure that the engine's idle speed is maintained at the correct level.

It is possible for the IAC to become stuck or dirty.  It may be necessary to replace it or clean it.  Here’s a great Video from YouTube 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.  It may be necessary to replace them if they appear cracked or dry-rotted.

Leakages around the throttle body and intake manifold can cause your Grand Cherokee Grand Cherokee to throw this code.  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-blocking passages.

The throttle body can become too dirty to allow air to enter the engine.  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.



It's possible to identify P0505 within your Grand 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.

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