Speed sensor check - 90 Accord EX

[Stites]

Hey all. I have a 1990 Accord EX that's had speedo issues for a few days now. I've checked the 3 wires going TO the VSS as per FSM directions, and I have continuity on the ground, battery voltage to the yellow, and 4.68V on the orange. The speedo still works from time to time... it just has me confused, because most electrical parts just quit completely, right? Is there any way to test the VSS? Thanks, y'all.

[jeffcoslacker]

Electrical wiring can do bizarre intermittent things, like sag and ground out if heat stressed and insulation burned, etc. Poor grounds are real demons too. sometimes when testing it can be useful to move the harness being tested around to make sure there's no glitches.

If you suspect a ground problem, you might try supplying an alternate ground to the circuit and see what happens.

Far as testing the VSS goes, I would think supplying 12v to the battery side, ground the other and read the remaining terminal for steady changes as the VSS's shaft is turned...it's just reading teeth going by the sensor, same as a crankshaft sensor or ABS wheel speed sensor...

[Stites]

I found a link that stated that the VSS does in fact die out slowly, more often than not. Got a new VSS on the way from Chandler Motorsports up in Wisconsin for less than $20! If that doesn't fix it... at least I didn't eat $100 on a new VSS. Thanks for the reply, my friend.