'97 OB Speedometer Death/Loss of Power/2 Error Codes

[rideabmx]

This is a fun one.

 

I was driving and my Speedometer started acting up (1997 Outback, 185k miles). It would show the correct speed while I hit the gas, but if I let off the gas it went haywire. I was looking at houses that day so I cruised around for a couple hours, mostly highway. The next day, my Speedometer was erratic all the time. About 30 miles into a highway drive, the Check Engine Light (CEL) comes on. As I'm pulling up to meet the landlord at a potential rental house, the car loses all power, starts running like complete crap, and generally acts as if it's running out of gas or something. I'm sure it looked high class to have the tow truck on its way as we toured the property with the landlord. When the tow truck arrived, the car started up and appeared to run just fine, but I believe that the CEL was still on. I didn't really drive it but a few feet; I had it towed to my very trusted mechanic.

 

My mechanic pulled the codes: p0505 and p1507. One indicates a problem with the VSS (0505) and the other indicates an IAC valve issue (1507). According to posts I've read on here, it seems like both could have caused my loss of power/crappy running problem. However, my mechanic has some sort of troubleshooting flowchart to follow and it says that if both error codes are present and the engine has no vacuum problems (or something like that), pursue the 1507 code and ignore the 0505 code--fix the IAC valve and ignore the VSS code. The problem is that there is no ignoring the VSS code since the Speedometer doesn't work.

 

So, should I do the opposite and ignore the IAC code and purse the VSS code for now? At least one post on here mentions that an IAC code could be related to a malfunctioning Speedometer:

http://www.ultimatesubaru.org/forum/showthread.php?t=27788&highlight=p1507

(last post in thread)

Since the Speedometer needs fixed anyway, this seems like a logical course of events.

 

...If only it were that easy. He threw in a new VSS and the Speedometer still didn't work (the VSS was also still outputing odd voltages). Assuming that the mechanism in the tranny that drives the VSS is a normal cog-to-cog gear setup, there should be no play if you stick a screw driver down in there. He did that and there was some play. So, he's thinking that the gearing system in the tranny that drives the VSS is stripped. Does anyone know if this can be replaced without pulling out/taking apart the transmission? If so, how?!?

 

To sum up:

1) Should I pursue the VSS issue over the IAC valve? Seems logical since I need a working Speedometer anyway and there is some indication that they could be related, regardless of what the flow chart says.

2) How do you replace the gearing assembly in the transmission that drives the VSS so it can output voltage?

 

Thank a lot, you all are a tremendous resource!

 

Josh Ellis

Leaburg, Oregon

[rideabmx]

Hmmmm..... This is going to be one of those posts I always find where someone has my exact problem but no one responded so it's totally unhelpful. Oh well, such is life. Once I figure out what to do I'll update this.

[1 Lucky Texan]

Could this something as simple as a bad/corroded ground or electrical connection somewhere?

 

 

I dunno, but I would definietly pursue the IAC issue first. The speedometer is the least useful gauge on the instrument panel! (yeah, I know the vss also feeds the computer.)

 

Carl

[rideabmx]

UPDATE: Replacing the IAC did not solve the problem. It is highly intermittent, with weeks going by without any issues and days where it falters every time I slow down.

 

It must be some sort of electrical issue, as mentioned. I think that I'm going to get a used transmission and replace mine because it needs done, and perhaps this process will fix the problem.