EG6 VSS aka Speed Sensor 78410-SV0-003

My Speedometer was behaving erratically.  Occasionally, when I start off after parking for some time, the speedometer will not move until I have traveled for about 15km, after which the needle will jump from 0km/h to normal.  It got worse as engine check light came on.

The VSS aka Speed Sensor signal goes to the ECU and Speedometer directly.  To verify if there is a VSS issue, I check using my laptop connected to my Hondata for VSS reading which show 0 km/h when i was on the move.  

Those not using any programmable ECU or no other way to check this, can try to engage VTEC while driving.  If the VTEC engages will mean that the VSS is still providing signal to the ECU (VTEC will only engage after certain speed, which is why VTEC will not work when the car is stationary, while trying to rev beyond VTEC engagement RPM).  Also to note, the CEL may come on if the reading stays at 0km/h (trying unplugging the VSS, the CEL will not light up).  The CEL only light up when my Hondata VSS reading stays at 8km/h throughout.

 

I found a real cheap VSS off Ebay for US$10, which is not Honda original part, but for the price I though it might be worth trying.  It comes with the Drive Link (the little pin).

 The VSS is held down by 2 10mm bolts, which is easily accessible, local on the gearbox near the firewall.

Old VSS removed

Drive Link inserted

New VSS installed.

Taking a closer look, the centre pin is corroded.  It may have solved the problem I had clean up the pin.

Besides changing the VSS,  I decided to clean up the pin in the plugs

You can see that the centre pin is corroded like the old VSS.

I decided to remove the pin to clean it up. First remove the white plastic pin cover.

Push down the pin and slide it through the back of the plug.

I used 500 grit sandpaper to sand off the corroded area.

Plug everything in and hopefully the erratic behavior will disappear :)