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1997 Mitsubishi Galant P0505 Code: Idle Problems and IAC Valve/Motor Diagnosis

Model: 1997 mitsubishi galant Fault Code: P0505 Posted: 2007-10-12 13:57

Hi there, I own a 1997 Mitsubishi Galant that has been experiencing idle instability at low RPMs and when the vehicle is completely stopped. The car runs fine on highways, but the issue becomes noticeable during idle conditions. I checked the engine light and found the diagnostic code P0505. I've consulted my Haynes repair manual, but I'm struggling to understand what exactly this code means in practical terms. Specifically, I'm unsure whether the problem lies with the Idle Air Control (IAC) valve or the IAC motor. The symptoms suggest a possible issue with airflow regulation at idle, which is commonly linked to these components. What should my next troubleshooting step be? Is it safe to replace just the IAC motor, or do I need to inspect both the valve and motor as a system? Any insights from owners of similar models would be greatly appreciated.

Related fault codes
P0505
Comments (3)
Anonymous 2007-10-12 15:54

Have you confirmed whether your vehicle has both an IAC valve and an IAC motor? These components are often integrated or separate, so knowing the exact setup is crucial for diagnosis.

Anonymous 2007-10-12 17:18

In most 1997 Mitsubishi Galant models, the issue with P0505 points to a faulty IAC motor. The motor controls idle air flow and is more commonly at fault than the valve itself.

Anonymous 2007-10-13 07:46

Yes, I have already replaced the IAC motor. After the replacement, the idle stabilized significantly, and the P0505 code cleared. This suggests that the original motor was indeed the root cause.