My 2000 Outback had the CEL come on and the code is 1505, the people at AutoZone said it was the Idle Control System Circuit. How do I go about trying to fix it myself?

 

Mark

Does the CEL stay on all the time, or did it just come on, and go out?

Came on returning from work on Friday and stayed after a few short trips around town on Saturday. Sunday it disappeared and it came back on my way into work this morning.

 

Mark

How does the car run? Is there anything that seems out of the ordinary?

The idle seems normal. At a complete stop I noticed a jolt a few times. It was similar to putting an automatic transmission in gear. I glanced down at the tach when I felt this happen and it appeared steady around 700-800 rpms. The AC was not, I checked the fluids this weekend and everything was fine. Car has about 180,000 mile on it.

 

Mark

This is a tough one to diagnose. P1505 is Idle air control at adaptive clip. Translation, something is causing the engine idle to change so much, the ECU has reached it's max either opening or closing the idle air solenoid and can no longer maintain the preset idle. You have reached the limit of Idle Air Control.

 

Now Why, anything from a misfire, but that code will also exist with the P1505, to a vacuum leak to a piece of foreign material causing the idle air solenoid to open and close properly.

 

I might start looking for a vacuum leak or cleaning the idle air solenoid. After that, your choice of what to try next. This looks like it can be almost anything, right down to a front oxygen sensor just enought out of spec to cause this, but not enough to throw an O2 sensor code. Even a fuel filter can cause it.

 

Get someone with an OBDII reader that can get you the Freeze frame data. That shows the status of all the sensors at the time the code was set. From there you might be able to see which sensor is 'out-of-spec' or reporting an out of spec condition that is causing the ECU to compensate by adjusting the idle. This is the only other piece of data I can think of to help you diagnose this.

 

Good Luck on this one....end of my $.02

<p>I have a 2000 outback and I'm getting two dtc's P1505 AND P03003 I changed the plugs, wires, and switched coils with one I knew was good. The symptoms are rough idle and when driving a hard jerk at lower RPM's in all gears. I'm an old school mechanic and to me it feels like what happens when you get trash in a carb (I know this car is not carbureted just using that as an example) The CEL was flashing then would go out and the car ran normal until the CEL would start flashing. I've used an Innova scanner on it and cleared it several times but it comes back within 10-20 miles of driving. What gets me is the problem is intermittent, sometimes it runs perfect sometimes it starts chugging. I'm going to recheck all that Subaru Nut posted in the previous comments but if anyone has any more info please share ASAP because I'm on a deadline with this car, Thank you. </p>

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<p>*Update* I got it fixed, #3 fuel injector plug was dirty and loose, used carb cleaner and rebent tabs inside of the plug. Cleared the codes and drove it 30 miles with no new CEL's </p>

Edited October 15, 201510 yr by timdove333