What the heck is the P1507 Error!?

I've been searching everywhere, but can't seem to find this error message code. It's not in my manuals.

[ame=http://www.youtube.com/watch?v=SQFt5wya6QQ]How To Repair A Subaru With The Mysterious P1507 Code. - YouTube[/ame]

I'm dealing with P1507 as we speak, with my 98 OBL (see posts about '98OBL with power loss...).

 

My P1507 accompanied the conditions of (1) very rough idle (to the point of stalling when I slow down, particularly going down hill), and (2) loss of speedometer (by not tach).

 

So far, it looks like one of three things (I would find it unlikely that it is all):

- neutral safety switch is bad, needs to be replaced

- IACV is dirty, needs to be cleaned

- vehicle speed sensor (this is the only one that would seem to explain the speedo problem).

- other possible causes others have commented on are loss of vacuum and loss of ground. If I can't solve the problem with no. 1-3 above, I'll start replacing my vacuum hoses to see if one has a small leak. Hopefully it won't have to come to that.

 

If you discover any new potential causes (or solutions!) to P1507, please share them, I woudl be interested to hear.

 

Cheers,

 

Aaron

 

At the moment, I am waiting for my new neutral switch and IACV gasket to arrive, so I can replace and clean, respectively, those two items. If these don't solve the problem, I'm going to move to replace the VSS (first need to order one).

I'll be sure to post what I find, my engine is all torn apart atm because I'm replacing the head gasket once that's rebuilt I'll start to troubleshoot this more.

usually it is a leak,

a vac leak on one of the hoses under the hood going to the passenger strut tower.

or the small filter in the hose going to the strut tower is bad, (rare)

or maybe even a leak in the gas filler neck.

 

with the engine idling,

spray carb cleaner, or staring fluid around the hoses .

if the idle surges you have found your leak.

P1507 - Idle Control System Malfunction (Fail Safe)

 

I read it could be as simple as a dirty sensor in the intake manifold.

 

Here are some reiterations and suggestions:

 

Turn ignition switch to ON. Start engine, and idle it. Check the following items.

 

• Loose installation of intake manifold, idle air control solenoid valve and throttle body
  
• Cracks of intake manifold gasket, idle air control solenoid valve gasket and throttle body gasket
  
• Disconnections of vacuum hoses
  

 

More reading on the subject:

 

Same code, car taken to dealer, they replaced a ground cable. Basically I learned that any time you have alot of codes showing and you don't think the respective parts are bad you should look for ground problems by checking for voltage drops. In this case I was losing 6 volts between the battery and the body grounding point. The problem was caused by a shady body shop that did body work under the ground and didn't sand the spot before replacing it (to achieve a good contact surface). They also mangled the wire. Once these issues were addressed ALL of the codes went away.

 

Even More:

 

Improper sealing of the IACV will Lead to ur symptoms.

Maybe this will add some light? neutral safety switch?

http://forums.nasioc.com/forums/showthread.php?t=1196685

My car is a manual and I've learned that the neutral safety switch doesn't exist on a manual transmission. Is that correct?

The hole engine is part now, probably can't troubleshoot until its built again?

My car is a manual and I've learned that the neutral safety switch doesn't exist on a manual transmission. Is that correct?

 

You do have a neutral safety switch (or at least I do on my 98 OBL manual trans). It is a short cable (~2 feet long) that has an orange/brown plug on one end that is visible under the air handler box (big black box in back center of engine). The other end goes to the transmission. Mine is screwed into the tranny and visible on the driver side of the trans.

 

I have a 'P1507 problem' I have been trying to work through, I I just changed my neutral switch yesterday. You don't need much- only a 19mm wrench, and to remove the cable from a few clips.

 

Unfortunately, replacing the neutral switch did not solve my P1507 problem. I am now turning my attention to cleaning the IACV, then vac hose leaks, then poor grounding.

 

I've seen mention of a few other possible causes which I will also look into. For now, I have 'P1507 fatigue', but I'm not willing to give up.

Im new to subarus all together and i have this code on my 2001 outback 2.5. What ended up curing you p1507 issue?

 

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Over on NASIOC, they say that it's the neutral switch causing the issue. The IACV being dirty can cause it too. I know on mine, the crossover pipe on the throttle body was completely clogged starving coolant to the IACV. I had weird idle issues before I cleaned it out. Now it's golden.

I've been searching everywhere, but can't seem to find this error message code. It's not in my manuals.

Po1507. Idle air control valve malfunction (failsafe mode)

 

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