I have a serious problem ppl.. Please help me.. just did a engine swap. I have a new h22 in my prelude.. sometimes my speedometer does not work. when it doesn't work my vtec also does not work. the engine codes are reading speed sensor. but its all the way plugged in. I just don't understand! its like there is a short some where. the speedometer chips in when it feels like. and the vtec with it.if its not working then vtec is not either. help help help!

 

If the VSS is bad the ECU purposely will not let VTEC work, most CEL will not let VTEC work, it's a fail safe. Get out a DMM, the factory service manual and figure out if it's faulty wiring or the sensor and fix it, you already know what's causing it.

 

swap out the vss

 

what mini said