I have a very similar problem as 987687 in this thread http://www.ultimatesubaru.org/forum/showthread.php?t=113447.

 

I have a 1997 Impreza L, 5spd MT. The speedo is cable driven and to the best of my knowledge I only have on VSS; located in the speedometer. I am getting codes P0500 and P1540, both related to the VSS. Sometimes while driving my CEL will turn off, and then in two or three miles turn back on again. I removed my gauge cluster and tried to bench test the vss and it seemed to Ohm out ok. I'm not sure if that is relavent or not. I have been to the dealer and they told me that my tires were different sizes (apparently the fronts wore about 1/4 of an inch more than the rears between rotations). They told me that this was my problem on the reasoning that wheel sensors send a wheel speed to my ecu which in turn sends a reading to the VSS.

 

I now have all the same size tire on my car, but I am still getting VSS codes and my car is stalling more frequently.

 

I am curious as to what I should look into next?

I have a very similar problem as 987687 in this thread http://www.ultimatesubaru.org/forum/showthread.php?t=113447.

 

I have a 1997 Impreza L, 5spd MT. The speedo is cable driven and to the best of my knowledge I only have on VSS; located in the speedometer. I am getting codes P0500 and P1540, both related to the VSS. Sometimes while driving my CEL will turn off, and then in two or three miles turn back on again. I removed my gauge cluster and tried to bench test the vss and it seemed to Ohm out ok. I'm not sure if that is relavent or not. I have been to the dealer and they told me that my tires were different sizes (apparently the fronts wore about 1/4 of an inch more than the rears between rotations). They told me that this was my problem on the reasoning that wheel sensors send a wheel speed to my ecu which in turn sends a reading to the VSS.

 

I now have all the same size tire on my car, but I am still getting VSS codes and my car is stalling more frequently.

 

I am curious as to what I should look into next?

The dealer is correct about the tire size being critical. But unless you have ABS brakes there are no wheel sensors on all four wheels. My '97 Impreza L with 5MT came without ABS (thankfully:)). What kind of readings did you get when you ohm'd out the VSS unit?

I do not have ABS so I don't have wheel sensors. When I ohmed the speedo I got a little bit of an erratic reading/ since its intermitten it was hard to tell what i was exactly seeing. It did give me a reading every fourth turn though. I think I may pull off my gauge cluster again tomorrow and retest it for some better/exact numbers.

 

Does the VSS read the cable speed and send that to the ECU if there are no wheel sensors?

 

Thanks

 

Ps I believe we participated in Paul Eklunds rally school this spring together. I was in the '08 Silver OBS.

Still getting the vss code, have a new used gauge cluster headed my way, hopefully that will correct the problem. Found out that part of my problem was due to two gasket leaks on my intake system. Looks like I had a multi-part problem

So I put in a new gauge cluster, it seemed to clear up the vss problem with the lowered rev limiter, but then the CEL came back on with the P0500 (vss code) again. Any suggestions?

Keeping my fingers crossed, but I may have found a loose ground that seems to have cleared up the problem for now.

 

For anyones future reference, if you are getting CELs and you have a scanner, check to see what kind of info your ecu is reading. Its possible that a ground is causing your problem instead of a sensor.