Jump to content
Ultimate Subaru Message Board

Recommended Posts

Hi all,

 

My research tells me that P1507 and P1540 mean IAC and VSS issues. I am going to pick up a VSS and slap it in (speedo and odometer are dead). But what I am wondering is if the P1507 (IAC) is perhaps a result of the P1540?

 

This car has 220km on it, I just did the head gaskets and I didn't have a scanner before I did the job so I don't know if the 1507 was there before I started but the speedo was broken prior so the 1540 probably was. Did I miss something during the intake reassembly? The IAC connection seems solid. The car runs nice and seems to idle ok too.

 

Any thoughts or tricks? Should I tear in and clean the IAC or do I even need to?

 

Dean

Share this post


Link to post
Share on other sites

Iac issue could be because the ECU thinks the car is sitting still.

 

Before replacing the VSS check to make sure the drive gear inside the transmission isn't broken. Also make sure it's not just unplugged.

Share this post


Link to post
Share on other sites

Yeah it's plugged in for sure, that was the first thing I tried. Is the drive gear attached to the sensor itself or do I have to poke my head in there to see if it's broken?

 

Thanks a bunch,

 

Dean

Share this post


Link to post
Share on other sites

Actually it's not visible on these. There is a notched shaft that sticks up that engages the tooth on the sensor. You have to remove the sensor, and either use a screw driver to try to spin the shaft in the transmission, or make a not of its position, then spin one of the front wheels and check to see if the shaft position changes.

Don't try to force the shaft to spin with a screwdriver. It should be very easy if the gear is broken or stripped. If it doesn't turn at all the gear is fine and forcing it could damage it.

Share this post


Link to post
Share on other sites

VSS - Like this - that 'blade' on the end can break - both on the electronic 1995+ and mechanical <1995 style:

speedoVSS2.jpg

 

I'd replace the VSS, reset the codes and bet you're golden!

 

 

vehicle speed sensor electronic - transmission - trans - 5-speed - manual - Automatic - Auto

Edited by wtdash

Share this post


Link to post
Share on other sites

I yanked it out the other day and spun the front passenger wheel, thankfully the gear in the tranny spins.

 

At first I was worried because I expected the gear to spin faster than it did - it just took a few rotations of the tire to actually notice the movement.

 

Out of curiosity I put the old sensor on the vice with a drill on the tab and my multi-meter attached to the points. The sensor was reporting intermittent voltage and seemed to crap out right away at low speeds - like I think it hit around 2 volts or so and then went dead after that. Picking a new one up from the dealer today. I'll update the results.

 

Thanks for all of your input!

 

Dean

Share this post


Link to post
Share on other sites

Hi all, first time to post, hope i can be clear... my '98 forester started acting funny a while ago. just a few times did the rpms increase, and there was loss of powe, as if in nuetral( itis automatic).  yesterday the check engine light came on and the rpm, powerless machine was taken to auto zone in 2nd gear for a code read.  got )500. replaced the vss. drove ok, but the light still on and now speedo quit. took it to advanced where codes 1507 1540 came up in addition to 0500. any ideas what i should do now? i am extremely low on funds, the $107.00 for the vss nearly killed me... thanks in advance for any ideas

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×