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Speed sensor talk.

Posted: Fri Mar 27, 2015 2:43 pm
by cj91legss
I'm in a bit of a dilemma on speed sensor signal issues, i.e. my speedo doesn't work because i completely forgot to grab a speed sensor. Well there's also an extension harness to go along with it that I don't have.

WRX is 3 wire.
Older VSS is 2 wire.

I know the pinout for the 3 wire, I have it printed, but I do not have the pinout for the 2 wire.

Can the 2 wire even be used?

Re: Speed sensor talk.

Posted: Fri Mar 27, 2015 6:35 pm
by 86BRATMAN
No insight, but I think I've got the vss extension harness from my 05 transmission laying around somewhere from when I swapped it into my 97.

Re: Speed sensor talk.

Posted: Fri Mar 27, 2015 6:43 pm
by cj91legss
What do you want for it if I can't get it from subaru?

Re: Speed sensor talk.

Posted: Sat Mar 28, 2015 3:51 am
by 86BRATMAN
Nothing. I don't see it costing more than a couple bucks to send it. Not worth a PayPal transaction.

Re: Speed sensor talk.

Posted: Sat Mar 28, 2015 3:52 am
by cj91legss
I'll take it!!! Still got my address?

Re: Speed sensor talk.

Posted: Sat Mar 28, 2015 3:57 am
by 86BRATMAN
I don't think I do, pm it to me. I'll get out in the building on Sunday and make sure I have it.

Re: Speed sensor talk.

Posted: Thu Apr 02, 2015 6:11 pm
by Legacy777
I looked into this when I was doing my hybrid UK gauge cluster swap and the difference between the 2 and 3 wire sensors is just how it's wired up. All the ECU is looking for is an "on/off" type signal. With the two wire setup, one wire goes to the VSS input on the ECU and then the other wire will either go to ground or to a 12v ignition switched source, depending on what the ECU is wanting to see.

For the first gen ECU, the ECU sources 5v through the wiring to the reed switch in the speedo and then it gets grounded. I would just look at what the WRX ECU wants to see and try to mimic that setup. If you would like help with anything, let me know. This is familiar territory for me.

Re: Speed sensor talk.

Posted: Thu Apr 02, 2015 6:13 pm
by cj91legss
I ended up getting a 3 wire sensor and harness. But I think the question could benefit others in the future.

Re: Speed sensor talk.

Posted: Thu Apr 02, 2015 6:14 pm
by Legacy777
Ok, so everything's working ok then?

Re: Speed sensor talk.

Posted: Thu Apr 02, 2015 6:15 pm
by cj91legss
Yes sir. I'll let you drive it next time you're in seattle.

As long as I don't blow something up in the meantime.

Re: Speed sensor talk.

Posted: Thu Apr 02, 2015 6:23 pm
by Legacy777
Sounds good :)