So my speedometer still does not work in my 95 EX Civic. I unhooked everything and took out the dash to see if i could find the culprit ( i do have a bit more than basic knowledge of wiring, etc.) First things first im doing some weight reductions so the AC box is now gone. As for the VSS sensor i tested the ground wire for continuity and it passed the test. Moved on to the yellow/blue wire and turned the ignition on and no dice. Says open circuit, so we turned the key off and it has continuity ???? weird. The last wire i believe was Yellow/White? and that was also an open circuit regardless of key on or off. I think one of those two wires may be the culprit, any suggestions ?

 

I would start by inspecting carefully the VSS connector itself for damage and the Yel/Blu and Yel/Wht wires for breaks before they merge into the main wire harness. You may also try making voltage measurements on those two wires just before the latter merger point to determine whether the open is located between there and the VSS connector. The latter tests would require you to remove a minimal amount of wire insulation. Those areas would need to be subsequently repaired to reinsulate the wires.

 

i tested at the connector and the results where the same at the connector by the driver side wiring harness, same result...i could not imagine why the speedometer would be bad , a buddy of mine who previously owned the car said that by wiggling the wires on the passenger side engine bay infront of the battery vtec would enage????

 

First off, start only one thread per problem, please.

At the sensor, with sensor plugged in and the key on, measure voltage to ground. You should have approximately 12 volts at the power wire (pin 2), The sensor must have this power to operate. Also check that it is grounded, there must be nearly zero volts on the ground wire (pin 1). Pin 3 is the output, it outputs pulses as the wheels turn. Thus to test it, lift one of the front wheels off the ground and put the transmission in neutral. Rotate the wheel by hand and you should see pin 3 pulsing on and off. I think it goes from about zero to 9 volts. If you see something changing as the wheel turns, the sensor is probably good.

Now go to the wires that go to the cluster and you should have the same pulses on pin D11 (yellow-blue wire) as the wheel turns. If not turn off the key and unplug the VSS and test for continuity from D11 all the way back to the sensor plug. I think it does go through the big harness plug on the right side. Also inside the car the VSS signal branches out to the ECU, SRS unit, and cruise control control unit.

If a good signal from the sensor is not reaching the ECU, the CEL will come on with the VSS code, and the VTEC will not work. Speedometers do go bad. Usually if the speedometer itself is the only problem, the odometer will keep rolling up miles as the car goes. Also the CEL will not be on.

 

so i take it my speedometer is good because my trip odometer doesn't move either ?

 

so i put everything back together and now believe pretty full-heartedly that my sensor is the culprit. Ground wire has continity at the sensor, when the key is on power is arriving at the sensor, but when i pick up one wheel and spin it no pulse or change in readings.

 

I hate to bump such an old thread, but it's one of the better ones I have found. You guys seem to know what you're talking about, I hope you're still active here.


Anyway I have some interesting results from testing my VSS and related wiring that baffle me. I'll keep it short and sweet.

'92 DX hatch w/ OBD1 B16A w/ Y21 LSD tranny
using an EX wiring harness

CEL code 17 and of course the speedometer isn't working.

ASG fuse is not blown.
Black wire has continuity to chassis ground.
VSS connector pin 1 (yellow/white) shows 12+ volts steady
VSS connector pin 2 (yellow/blue) has continuity to the cluster connector.

With ignition at ON position, VSS connector unplugged pin 1 (yellow/white wire) shows 12+ volts, and pin 2 (yellow/blue wire) shows 2.65 +/- volts pretty steady.

How could the yellow/blue signal wire be getting voltage?

With one wheel off the ground, ignition at ON position, VSS connector plugged in yellow/white wire shows 12+ volts, and yellow/blue wire shows 2.65 +/- volts pretty steady. When the wheel is rotated, no fluctuation in voltage. I have tried 2 different VSS with the same results.

Would replacing the yellow/blue signal wire be a logical next step?

Also, how fast do I have to spin the wheel to get the fluctuating signal?

I'm not sure if it's the fact that it's an LSD tranny or not, but the wheel is very difficult to rotate, and I'm kind of a big guy (yes, it is in neutral).


Anyone have any ideas?



This is more detailed than my pos Hayne's manual, thank you.

 

It's common for the pins in the sensor plug to be corroded or bent and not make contact. The 2.5 volts could be coming from the ECU, cruise, etc. all are connected to the signal wire. Do you have that same voltage with the sensor unplugged?

Try taking the sensor out and turn just the gear on the end. If that works, the gear in the transmission could be bad, or the sensor is not the right one.

With a LSD transmission, you'd need to lift both front wheels off the ground. When you turn one in neutral (which should be easy), the other one would turn in the same direction.

 

The terminals of the sensor and it's connector are both corrosion free.

I have dealt with that before and I assumed that was the problem from the get go.

Yes, plugged/unplugged same voltage.

Great idea, I'm a little embarrassed that I didn't think of that.

Ok I'll try that, it's just that the manual made it seem important that the other wheel wasn't able to rotate. It seems to me that it shouldn't matter.

Thank you sir.

 

Standard differential you can't let the other wheel rotate, as it can turn backwards while the input side doesn't turn.

As the voltage doesn't change at all when unplugging sensor, I'd think the circuit to the sensor is broken.