TylerVDB

Ok, I have 1997 Civic with an f20b. It has been great for about a year, recently my speedo quit. I know the easy answer is vss and I wanna think I know what I'm doing but my question is: With the vss unhooked and my multimeter connected to the plug I'm getting ground out of black for sure, meter screams at me lol. The middle wire though I'm getting 8.4v and the other is getting 4.9v...is this correct? Shouldn't one be 12v? And am I too suspect a bad vss since I'm getting voltage and cont.?

TylerVDB

Bump...

TylerVDB

My main question is, since I'm getting voltage and ground at the plug, that means the vss is bad right? And there is no open in the wires. Next question is, will the f23a1 vss work on my t2t4 trans? Its the only one I can find with the bottom gear and shaft that actually go into the trans. (t2t4 is essentially an f23a1 trans from what I've read).

Former User

The reading should be within 1 volt or so of the voltage reading across the two battery posts.

TylerVDB

That's what I thought also. Kind of odd. But does it sound like my vss is the culprit? Since I have cont for ground and voltage out of the plug this at least means I don't have any opens? Also, will the f23a1 vss work for my t2t4? Thanks for the reply btw, was getting worried no one would help me out before I spent $70 on a vss...

Former User

Maybe I misunderstood something. Weren't your continuity and voltage tests done on the unplugged VSS connector? Please clarify. If so, the unexpected low voltage (8.4V) could not be caused by the VSS itself because it was disconnected from the circuit you were testing.

And what is the voltage reading across the 2 battery connectors?

In your voltage tests, did you use the black wire terminal in the VSS connector as ground?

TylerVDB

With the plug disconnected, checking for an open is what I was doing lol. I read one of your posts about the vss situation and the key on test and key off cont test to make sure I didn't have a break in the line somewhere. And then I even raised the wheel to spin in and test on the vss itself. Pretty sure my vss is just dead. Now I'm stumped on which one to buy for my t2t4.

12.4v, odd for it only to 8.4v out of the plug with key on right?

Yes, I used the black as ground.

Former User

Why are you focusing on the VSS when you have an out of spec voltage reading at the VSS plug (could be caused by pinched wire, bad contact in a connector or fuse 15)? This low reading cannot be explained by a bad VSS. Fix the low voltage problem and then go from there.

TylerVDB

I would still like to know which vss to buy lol. Since I know it's dead also...But yes my next step is finding out why I have low voltage at the plug itself. Plug has been rewired at some point so I'd say it's where the previous owner didn't solder or whatever...All of this aside, I need to get a vss coming and in the meantime I'll worry about the voltage. Will the f23a1 VSS work?

Former User

How do you know?

Former User

I inserted this^ question into your thread title.

TylerVDB

Rasied the car spun a wheel and looked for 5 volts at the sensor...notta.

Former User

This might be caused by the low voltage issue. Don't buy a new VSS until you know it's bad. Fix the voltage issue and go from there.

TylerVDB

Thanks lol. So, you dont know if it'll work either? Lmao. F23a1 looks exactly like what came out of it. Black plastic single unit unlike the older ones that have the sensor on the top.

TylerVDB

How would that have something to do with the voltage issue without the vss plug hooked in? I had the multimeter inside the sensor on the terminal as my dad spun the wheel. From the tests I've read about it should blurp something, even went into mV to see if it was blurping at all...

TylerVDB

Next question though lol, does the 12v source wire run from the ecu? As is does the ecu kick it on or does it come from ignition source like fuse box? Reason I ask is if its not run by the ecu, can I just run a new wire to the vss for 12v instead of breaking my harness down and searching for it??

Former User

You're making a leap of faith that the VSS can operate properly at any input voltage. This could be wrong.

Try this bench test:

1. On the bench, connect the VSS power terminal directly to the + post of a fully charged battery and the VSS ground terminal to the - battery post.
   
2. Now turns the VSS gear by hand and check for resistance/Ohm oscillations from the 3rd VSS terminal.

Former User

The VSS receives voltage from the battery via fuse 15 (Blk/Yel wire).

The VSS receives low reference voltages (Blu/Wht wire) from both the ECU and cluster. The VSS grounds these reference voltages.

The VSS black wire supplies ground for both voltages above.

Former User

You make statements as though you understand how the VSS works, but it seems that you don't.

You are not providing sufficient details for anyone to know whether you did this^ electrical test correctly.

TylerVDB

Ok well I guess I should have thought about the sensor needing power/ground to do its voltage cycle when the gear is turned. Sorry it's been a long couple days. Just installed a camber kit on the rear and it didn't want to cooperate either, frozen bolts suck. But I'll bench test it this afternoon. As for the low voltage problem, I can just run a new wire to the VSS plug from fuse box for 12v is what you're saying?

Former User

Yep, but resistance test fuse 15 just to make sure it's good and not partially melted.

TylerVDB

Awesome! Sorry about being confusing. Like I said, been couple hectic days. I'll let you know how the bench test goes. Thanks again Ron! I still need to figure out which VSS to buy if this one is done for, so if anyone can help me out there...lmao.

TylerVDB

RonJ, looking at the sensor from left to right with connector/rails away from me, its ground, power, signal correct?

Former User

pin 1 = black (ground) wire

pin 2 = Blk/Yel (power from fuse 15) wire

pin 3 = Blu/Wht (vehicle speed input) wire