ready4anewhip

ok, so the speedometer was working fine then it started jumping up and down then car stalled out a couple times while i was cruising...
I found that the ground was very loose to the speed sensor..
i tightened it and got back in the vehicle to test, well i noticed the speedometer was not workin at all now. :?

I replaced the entire speed sensor thinking it maybe could have arched and fried it, well turns out thats not the problem now either because the speedometer still does not work.

ive checked every fuse in my car and nothing is blown or out of spot?

ANy help please???

Fabrik8

Check continuity between the speed sensor connector and the cluster connector. It's a 3 wire hall effect sensor if I remember correctly, which means that one of the wires will be a 5V supply from the the ECU or cluster (I can't remember which one supplies power, but both the ECU and the cluster are connected to the VSS output signal). I think the middle wire is the output signal, so you should have 5V between the outer two wires when measured with a multimeter.

When you say the ground was loose, what do you mean? Do you mean the mounting bracket that holds the sensor to the transmission?

crasy87rexsi

actually its 12v, signal, ground

The ground for it, is the one on the thermostat housing...which just so happens to be the ground for the ECU.
That would also be the reason the vehicle cut off.

BTW this pic is for a 95 civic...let me know and I will upload the one for your vihicle

Fabrik8

Oh, ok. Many are 5V and get power from the regulated 5V sensor power supply from the ECU, but 12V (unregulated) are pretty common also. It's been a while since I had a Honda.

crasy87rexsi

I had to think about that for a minute, I knew I had checked one one time and found 12v, just had to make sure.

Fabrik8

Yeah, the schematic you posted clearly shows 12V. I think all of the Honda VSS are of the same electrical type, just slightly different physical packages over the years. I guess that makes sense though, using 12V and chassis ground when distributing the signal to a few devices solves a few problems that would ordinarily occur with the sensor ground for the 5V sensor supply. That ground (for the sensor supply) can't be distributed the same way as chassis ground because of noise and some other things.

crasy87rexsi

Yea they all are, well 88-01, haven't really messed with anything above those years well at least not the VSS on them anyways. Not sure why they didn't do those like they did OBD2 harnesses where the 12v comes from a distribution block(plug) on the engine harness, OBD1's have the same thing just not as many sensors using 12v as compared to the OBD2.