So this car was running great, and I was really happy with it. Stopped into the parts store to pick up some panel clips for the car. Came out started it and got a P1507. 

Idle control in fail safe. 

Looking on line a fix seems to be the neutral switch. But I have an automatic so that can not be it. 

Also the car is running and sounding rough. and even seems to be shifting odd. Is this all related to this code? 

 

I am trying to see why it would start after a quick stop like that, and also if the other issues are related to it or not. 

 

Thanks

 

What year/model do you have?

 

Just because you were doing something innocuous and a code appeared doesn't mean anything. Read up here:

https://www.google.com/search?q=P1507.&oq=P1507.&aqs=chrome..69i57&sourceid=chrome&es_sm=93&ie=UTF-8#q=p1507+subaru

 

I skimmed a few forum links from that search at the top and most are saying it might be a ground issue. 

Sorry it is a 99 outback. A ground could be it? I reset the code, and this morning it is running fine. Thanks, I did a search and most of them were about the neutral switch.

 

This car is new to me, and I am new to Subaru. So I will do some searches for where to check grounding at. 

I would try cleaning the IACV first.

 

Automatic still uses the Park Nuetral switch on the side of the trans to tell the ECU what gear the transmission is in. When this code is set its because the ECU is trying to set idle speed at a certain RPM and it can't adjust the IAC far enough to do that. When the neutral switch on a manual trans car causes this code it's because the ECU thinks the trans is in Nuetral so it tires to set idle speed when you take your foot off the throttle, when it's really in gear and coasting with no throttle. The ECU can't bring the engine down to idle speed in a set amount of time, so it sets the code.

I wouldn't rule out the p/n switch just because it's an automatic, because there is the possibility it could cause this code, but I would try some other simple things first, such as cleaning up ground connections on the battery, engine block, and body, and cleaning the IACV.

Also check for any broken or split vacuum hoses, and make sure all of the breather hoses are properly attached to the intake tube.

ok, The idle is at about 1350rpm when in park and about 800 when in Drive. is that normal? or is that leading towards the p/n switch? I need to look at the paperwork I got with the car. I believe they cleaned the IAC and throttle body, as well as an adjustment to the p/n switch. and a few other things. And after their mechanic put the wrong computer in the car, I probably should not trust what he did..

Does it idle that high all the time or only when the engine is cold immediately after starting?

 

Normal idle speed should be about 750 rpm.

it idled high when in park both warm and cold. now it seems to idle ok. 

I will pull and clean the IAC tomorrow and see if that fixes this issue, I will also check grounds? From looking around, sounds like that may contribute to the issue,.I work weekends so tomorrow is the first day I get to work on it.

not a good day. Should have left it alone. 

I pulled and cleaned the throttle body, and the IAC valve. Now the car runs like crap. 
Has a miss, and no power. both of them seemed to be clean. Cleared the codes, and the car does not have a code, 

 

What could I have done to cause this? Should I start a different post? 

 

Thanks

Doug

Edited April 25, 20169 yr by whynot

now I am very confused and need some help. 

 

I went out and checked everything I had done, and even sprayed starting fluid around when it was running to check for a leak. Everything is connected, I started the car, and it ran ok, took it for a drvie and it ran good. pulled back into the yard and the crappy running came back, and again has no power.  This lis back to the same thing that started all of this on the way home one night and a quick stop into the store. Only code that gets set is p1507. 

 idle control in fail safe.

I think I found the issue. The car when warm is idling too high. Although the IAC looked like it had been cleaned before. So I adjusted the cap,to bring the idle down to about 750rpm. And so far the car is running fine, and no codes. Will update this again in a few days....