IAC P0505 advice

[ibtheoneny]

Hello everyone I'm a noob to the forum. My sister's 2000 Galant has a P0505 code. I cleaned the Throttle Body and removed the IAC motor and cleaned the passages. I went to the junk yard got a few IAC motors replaced the original with one of the ones from the Junk yard. I did the ohm test on all three and they were all within specs which was 30.1 ohms. She drove it all day and the CEL came back on. I wanted to see if the gears were still working on the motors so I unplugged the IAC on the TB abd plugged the ones I had without installing them and turned the key and saw them engage even heard the buzzing sound they make when you turn the ignition switch. They were all good and the car idles around 800-950 and I did the AC and turning the steering wheel and the idle changes. The only thing I haven't done is clean the EGR valve or the MAF. I checked all the vacuum hoses and found no leaks. Any advice? I apologize for writing so much but I just wanted to make it easier for you guys to understand all the steps Ive taken so far.
BTW
I have a live data ODBII scanner so I can monitor all the sensors

Thanks in advance

[4g63lover]

I have the same issue. Though I havent tried a different IAC yet.

[Colton5419]

My car was actually throwing the P0507 code, which appears to be similar to the P0505 code. I had my IAC Motor replaced and to make a long story short now have the ORIGINAL UAC back in and haven't had the code come up - I've driven over 300 miles on the original. The only difference is that I've cleaned my MAF Sensor since then with MAF cleaner from advanced auto parts.

The only reason I could come up with was that about a month before then I cleaned my throttle body with rubbing alcohol and a rag while it was still installed in the car. (My assumption was that some of the rubbing alcohol dripped onto the sensor)

If I get the code again I will try to clean the IAC motor sensor as well.

[ibtheoneny]

Just got a spare IAC and MAF from Junk yard, going to swapped them. I also want to add that I removed the Throttle body and cleaned it thoroughly and the code came back on. Its becoming a PITA.

[ibtheoneny]

Swapped MAF sensor although I doubt that is the issue. Unplugged ECM all night will plug back today. Anyone had this problem? I searched all posts but didnt find an answer. Any help would be apprecieated.

[fisherca22]

I had the same issue in my 2000 2.4L galant, I went to the junk yard and got two IAC, cleaned the throttle body and egr valve, checked for vacuum leaks cleaned the fuel injectors and the same code was there. Then the code just went off one day after filling up at a gas station I normally don’t go to. It turned out the cheap gas I had been using kept throwing the code somehow. A few months went by with no code, then I saw cheaper gas and filled up my car ,then the P0505 code came on immediately, so I waited for the next fill up and got as much as that gas out and went to a chevron to fill up and the code went off just like that. It’s been about year and half with no code not showing up I just fill up at the same chevron gas station every time now.

[ibtheoneny]

I had the same issue in my 2000 2.4L galant, I went to the junk yard and got two IAC, cleaned the throttle body and egr valve, checked for vacuum leaks cleaned the fuel injectors and the same code was there. Then the code just went off one day after filling up at a gas station I normally don’t go to. It turned out the cheap gas I had been using kept throwing the code somehow. A few months went by with no code, then I saw cheaper gas and filled up my car ,then the P0505 code came on immediately, so I waited for the next fill up and got as much as that gas out and went to a chevron to fill up and the code went off just like that. It’s been about year and half with no code not showing up I just fill up at the same chevron gas station every time now.

Ive asked her to do this and see where it leads. I will try going back to the junkyard get a few tps and try to find a v6 throttle body. I dont want her to have to shell out 300.00 for an IAC motor when all 3 are working just fine. Checked the wiring, harness and vacuums and all is in great shape. Any other suggestions will be greatly appreciated. BTW the car does have an exhaust leak in the flex pipe but I dont think that would be it. Sometime this week I will replace the t-stat and flush it cause its not green anymore.