I recently bought a 93 eg civic hatchback b20b4 (OBD2) swap the car starts a drives fine, but after a while(10-15 min) of driving my check engine light comes on, the car still runs fine and all. So I pull over turn the car off for a little then turn it back on, the car starts and drives fine and the light is off, then comes back after driving for a little. My speedometer also doesn't work at all. Could this be the problem? I pulled the CEL code and got 17 witch is VSS (vehicle speed sensor) will the VSS fix my speedo and CEL?

 

Yes, it should do.

The speed sensor screws into the top of the transmission (near the dipstick). It measures rotation speed of the axle, and from that tells the ECU what the road speed of the car is. The ECU uses that information to do two things: to tell the transmission when to change up and down (from the road speed and engine RPMs it can work out when the optimal moment to change is) and to display the speed you're doing on the speedometer.

If the speedometer is completely dead, then that is consistent with a failed speed sensor. Aftermarket ones cost around $20 on Ebay, and fitting it is very easy.

 

My car is a manual so what do you mean when you said?
"The ECU uses that information to do two things: to tell the transmission when to change up and down (from the road speed and engine RPMs it can work out when the optimal moment to change is)"

 

i would first check the pins on the sensor. they corrode often.

 

I haven't worked on a manual Civic. I'm guessing that they will have a similar VSS in the gearbox, but which only drives the speedometer (i.e. the ECU doesn't so anything with the data from it other than using it to operate the speedo).

 

auto, manual same principal. to tell the speedo to display a speed at which you are going. check the plug wires and plug condition and get a new vss. grab one from the junk yard. much cheaper.

 

Corrosion.........worst thing to **** with.