Jump to content
Ultimate Subaru Message Board

1999 legacy "At oil Temp" light flashing


Recommended Posts

I just baught a 99 outback runs and drives grate except after the AT oil temp light starts flashing I have pulled the codes and get P0500, P1540 both of witch from what I  found say vss (vehicle speed sensor) and from what I can see tells me I need the harness with all three vehicle speed sensors for the transmission not sure if this is correct. I have recently serviced the transmission check all differential fluids and everything works well except when the light starts flashing it feels like the torque converter is locking up and wanting to stall the vehicle at a stop I put the car in neutral to prevent it from hapning. I am also geting coat p1121 neutral position switch,and p1120 throttle position sensor will the vss put those sensors out of perimeter? Any help would be greatly appreciated thanks in advance

Edited by Danno-L
Link to comment
Share on other sites

Thanks fpr the reply I really appreciate it. I can still rev over 4500 rpm and has plenty of power which is confusing me on the symptoms? I will do some more investigation as the harness is about $300 and I want to make sure I'm not just throwing money at something to not fix the issue again thanks for the response 

Link to comment
Share on other sites

yeah i would diagnose if you don't want to throw money/guess, transmissions are hard to diagnose. 

check voltage/power - make sure you have excellent power source and connection, and the crank pulley isn't separating.  poor power supply can cause dirty signals and bogus codes. 

check the transmission pan and make sure it's not dented, or previously replaced thereby suggesting it was dented/repaired.  doesn't look related to your codes, but easy enough to look.

did you buy it with all these known issues?

8 hours ago, Danno-L said:

Thanks fpr the reply I really appreciate it. I can still rev over 4500 rpm and has plenty of power which is confusing me on the symptoms? 

i would not assume that symptoms will be identical every single time.  but you don't have an inoperative instrument cluster odometer/speedometer either do you?

Link to comment
Share on other sites

Yes the speedo works intermittently when it wants to. I've checked the wiring on the back of the dash Speedo unit has been replaced once and nothing looks corroded. I tested the ground on the dash cluster and had good continuity so I dont think it is the Speedo unit and that being said in going to order the vss harness everything keeps pointing back to it from what I can find . It's a little different than an old square body Chevy LOL

Link to comment
Share on other sites

No the issues started about halfway home after I bought it. It was a one owner car by a little old lady, I dont think she even noticed these little quarks but I dont want to destroy the tranny. and I now when lights start flashing something is bad enough to do damage. Also this is my first Subaru and they have a few more eltronics than im used to. Im going to check voltage at the crank sensor and the revolutionary sensors on the transmission thanks to all lots of good information

Link to comment
Share on other sites

If you're getting an assortment of codes thrown, it's probably a systemic fault (as suggested above) rather than anything wrong with the harness itself or any of the errors indicated.  My experience with this a few years back (also on a '99 OBW, EJ25D) was that after doing a motor swap the transmission was acting really wonky e.g. the 3-4 shift points were drifting all over the place.  I read the xmission controller codes, and they were telling me that there was a problem with communication between it and the ECU.  So I got out the 'scope and poked around and everything looked okay, and someone on one of the other fora suggested a ground fault, and I kinda thought it a crap suggestion, but went through the TSM to spot all the under-hood grounds, and although they looked okay I reterminated all of them anyway, and the problem persisted.  Ultimately, I settled on the ground not indicated in the TSM diagrams - the one on top of the intake manifold next to the coil pack.  Captain Dumb@$$ had failed to tighten that one down after the motor swap.  Did so and everything got better.

So it's easy to say "look for bad grounds", but there's nothing like one for making crazy errors appear all over the place.  That's where I'd start.

 

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...