Vehicle Speed Sensor

Maintenance/Repairs
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1

I have a 1997 impreza and a couple months ago I got a check engine light for the vehicle speed sensor. When the light is on the car goes into a limp mode and won’t rev past 4k rpms. The spedometer still works fine and the speedometer cable seems fine as well. I am stummped as to what keeps sending my car into limp mode and how to fix it!?

2

Exactly what was the code? P1501? P1502?
Did you get it fixed?
Have you since had it checked for other stored codes?

3

It was P1540, and no, its not fixed.

4

Also a P0500 code

5

Your vehicle has two Vehicle Speed Sensors. One is on the transmission that sends a signal to the computer, and the other is located behind the instument cluster for the speedometer. If the speedometer is working, then the VSS mounted on the tranny for the computer must be the one that’s causing the problem.

Tester

6

I have been working on this problem since I last contacted you and it is starting to consume me. Here is the update:

I could not find a VSS on the tranny, and according to the factory service manual for my year of impreza, it does not show one on the tranny.
I have a short cable coming off the transmission which links to a second, longer cable that goes into the back of the speedometer housing. To the best of my knowledge:
The cable spins and a magnet in the vss converts it to electric pulses every quarter turn. These electronic readings are then sent to my ECU.

I replaced my gauge cluster so as to install a new vss in the speedometer head, but I am still getting the p0500 code.

I had it in to the local dealer and they said that the problem was due to having different tire sizes on each of the four wheels. I measured the tires and there was between 1/8th and 1/4inch difference in the front and rears.

I put on new wheels and tires that are all brand new and the same size, and I am still getting the code.

I have my original gauge cluster out of my car and I am able to check the ohms, but I don’t know what the proper reading should be to see if that vss is out.

Also I was curious if the size of my tires could be throwing the vss off, because they are not the stock size?

I have all the tire information here:

Current 165/65R15
What car says: 195/60R15
Previous tires that wore differently: 185/70R14