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2001 Infiniti I30T P0505 Code: Idle Issues After IAC, TPS, MAF Replacement and ECM Update

Model: 2001 Infiniti I30T Fault Code: P0505 Posted: 2014-07-07 12:09

I recently replaced the Idle Air Control Valve (IAC), Throttle Position Sensor (TPS), and Mass Air Flow (MAF) sensor on my 2001 Infiniti I30T. The vehicle's ECU was also updated by a professional service shop. After these repairs, the idle speed has increased to 1500 RPM and the car hesitates when driving down the road. Despite the replacements and update, the OBD2 code P0505 persists. I've tried performing an idle learn procedure but it hasn't resolved the issue. Any insights or troubleshooting steps for this specific fault on a 2001 Infiniti I30T? The vehicle previously idled smoothly, but now requires constant throttle input to maintain idle for more than 20 seconds before stabilizing.

Related fault codes
P0505
Comments (4)
Anonymous 2014-07-07 12:32

I experienced the same P0505 code along with 0171 and 0720 in the past. After replacing several components, those codes disappeared except for P0505. The car would idle normally at first, but if I didn't keep my foot on the throttle for at least 20 seconds, it would stall. I attempted an idle learn procedure, but it did not resolve the issue.

Anonymous 2014-07-07 16:14

For detailed information about P0505 and its troubleshooting steps, refer to the official OBD2 trouble code guide available on this forum. It includes comprehensive explanations and step-by-step diagnostics for common causes of this error.

Anonymous 2014-07-07 17:51

Check out this authoritative resource: http://www.obd-codes.com/p0505 - it provides a clear breakdown of what P0505 means, possible root causes, and recommended diagnostic procedures for vehicles like the 2001 Infiniti I30T.

Anonymous 2015-10-18 20:28

I replaced my IAC valve, but the ECM still shows poor performance. When tested with a multimeter, the IAC appears to be functioning electrically. However, when I connected it directly to the power source and cycled the ignition, it showed no movement. This suggests a mechanical or wiring issue. Any suggestions on how to proceed? I'm at a loss as to what the next troubleshooting step should be.