Cadillac SRX P0505 : Idle Air Control System - Malfunction

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

P0505:  Idle Air Control System:  Malfunction

P0505 usually occurs due to a stuck idle valve or clogged idle valve.  Other causes can also be involved.  Although, they aren’t as prevalent.

P0505 Symptoms:  Cadillac SRX

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
• Low idle speed 

SRX Causes P0505

P0505 will usually indicate a vacuum leakage or a problem in the idle air valve.  While replacing the idle air control valve seems like a good idea, it’s worth your time to check for a Vacuum leak first.

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.

You can either get the IAC valve 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  

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

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

Carbon Buildup

Carbon buildup can occur around the IAC's inlet.  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.  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.  This problem is usually solved by cleaning the area around the throttle blades.

Conclusion

You will be able to diagnose P05055 in your SRX.  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.