VSS Issue - Voltage/Output/Sensor

[Dc2-ProductionS]

Hey guys, need a little help diagnosing an issue we are having with VSS. We are not getting a reading on speedometer and we cant track down the issue...some notes below

- since day one, I have not seen Speedo needle move. Tach works, lights in cluster all functioning, temp needle and gas needle all functioning.
- swapped to a different VSS unit. (Little different shape to housing, but same gear and length and plug) No dice
- checked VSS unit against multiple images and pictures and put correct unit into trans. (we had taken the ones i have in and out a few times at this point to test and not sure which was in first) Right one is in now....
- swapped engine harness (We had some broken plastic and tabs, coolant fan wasnt coming on, and hoped maybe VSS wiring issue) no luck. fan is working now as it should, still no VSS. Harness looks good though! LOL
- went through the manual and checked two fuses it referenced, both were good.
- VSS troubleshoot begins a voltage check with a "test relay harness"... basically an in-line harness with test leads coming out of it.... Yeah, dont have that.... So we used a meter to test. Harness has continuity at signal wire from engine harness end at VSS plug to Orange wire at ECU plug. Ground wire on harness end is grounded.... Now here is where sh!t goes weird....

The power/voltage at the harness end is reading 145.xx volts.... HUH? Something is not right... We disconnect the Orange wire coming out of ECU and test the voltage coming out of the ECU at that pin and its 145.xx.... Power on, this ECU is outputting 145.xx volts.... WTF IS GOING ON.... ECU fried?? Let's plug in another.

- swap out for another OEM ECU, test pin again, same thing. 145.xx volts...... WHAT IS GOING ON! LOL


I'm all types of ears for suggestions. We had gone through what I had thought was all of the ground locations and cleaned them up, maybe we check that again??

Also a kicker to boot, my radio does not work... It has worked intermittently prior, but now does not turn on. It's got power because security light is flashing..... (This is just a footnote of other electrical demon in case somehow in same circuit or wiring?? I don't believe so however)


HELP!!

[coolhandluke]

My gut is the radio and VSS/speedo are separate issues.

VSS:
*You are starting with the right approach with a multimeter. If helpful, I can pull out my Helm manual to see.
Digging back to 2007-2008, I had an issue in 98-1040 after the rebuild with the speedo not working. At the annual community Thanksgiving Meet Walker + B18Cxr helped trace and we ran a net-new wire from the ecu to the VSS

Radio:
*I would start with a new ground
**Pull radio and confirm pigtail harness connections, ie soldering/crimps are still secure
***Then '' on Helm references if beneficial
****If needed, pull dash and replace dash harness (I might have a spare)

[PatHidden]

It has been a while since I messed with b series stuff but just a couple of thoughts.

I think we need to determine if the speedo gauge is the issue vs the vss being the issue. (or wiring)

Are you throwing a vss code? From my experience, a code would be present if the sensor has an issue.

One simple check is if vtec is engaging, because vtec needs a vss signal to work. Granted you're confident there's no other issues, if vtec works then your vss sensor is fine. If that is the case, then it's an issue with wiring to your cluster or your cluster is an issue.

In the honda manual there should also be a flow chart when diagnosing a vss. One of the tests, IIRC, is to take a test light to signal output and rotate the wheels. If the test light goes on and off, the vss is working. I believe it similar to testing an ignitor on the distributor.

[Dc2-ProductionS]

It has been a while since I messed with b series stuff but just a couple of thoughts.

I think we need to determine if the speedo gauge is the issue vs the vss being the issue. (or wiring)

Are you throwing a vss code? From my experience, a code would be present if the sensor has an issue.

One simple check is if vtec is engaging, because vtec needs a vss signal to work. Granted you're confident there's no other issues, if vtec works then your vss sensor is fine. If that is the case, then it's an issue with wiring to your cluster or your cluster is an issue.

In the honda manual there should also be a flow chart when diagnosing a vss. One of the tests, IIRC, is to take a test light to signal output and rotate the wheels. If the test light goes on and off, the vss is working. I believe it similar to testing an ignitor on the distributor.

I do have a JDM cluster, then the speedo would (potentially) work and the tach wouldnt. But that's ok, i know that works.

I have been reluctant to cross 6k because vteXs!! Wanted to have everything in order before I do that but I might just have to go for it....

I did see something in manual about a signal and rotating the wheels. I will have a look back at that also.

I really hope its not the cluster...

[Dc2-ProductionS]

My gut is the radio and VSS/speedo are separate issues.

VSS:
*You are starting with the right approach with a multimeter. If helpful, I can pull out my Helm manual to see.
Digging back to 2007-2008, I had an issue in 98-1040 after the rebuild with the speedo not working. At the annual community Thanksgiving Meet Walker + B18Cxr helped trace and we ran a net-new wire from the ecu to the VSS

Radio:
*I would start with a new ground
**Pull radio and confirm pigtail harness connections, ie soldering/crimps are still secure
***Then '' on Helm references if beneficial
****If needed, pull dash and replace dash harness (I might have a spare)

I could do that for now with wire just to check it, but I don't want to leave it like that. There has to be something causing it! The voltage coming OUT of ECU is scaring me....

[Stin1]

You most likely had a rodent munching on the harness if it’s the original cabin harness. As asked earlier you can determine the ecu is getting it’s connection by trying to activate vtec at 6k. If it’s working you can narrow it down to something with the cluster or between.