I just swapped a second gen b16a into my buddy's 93 hatch cx. It's throwing a code 21 (VTEC solenoid valve circuit). I've already verified continuity b/w the ecu pin D6 and body ground and b/w the VTEC solenoid harness connector and ecu pin A4. I've verified that there's no continuity b/w the VTEC solenoid harness connector and ground. I checked continuity b/w the VTEC solenoid valve connector and body ground (should be 14 to 30 ohms), and there was none, which would signify a bad VTEC solenoid. So i put my VTEC solenoid off of my car (which i know is good), and it still threw the code (though I didn't check continuity b/w the VTEC solenoid connector and body ground). Any suggestions? Thanks in advance.

 

did you reset the ecu after you put your solenoid on the car?

 

I don't think I did (I know I reset it but I think it was right before that and for a different reason), but I do know that the solenoid that came in his car works because I tried it on my car and it was fine, which leads me to believe that the problem is something other than the solenoid. I'll try that though just to be absolutely sure. Thanks for the advice.

 

check the fuse box some times something little **** ish up good luck

 

This happened to me the other night, I was putting in my Pivot A/F meter and when i cranked up the car to make sure it worked properly. CEL came on w/ a code 21. I tore my hair out for an hour checking wiring and such and finally found the problem was that when i plugged the wiring harness back into the ECU it was pushing the pin out a little, just enough to not make contact. After reconnecting the pin and resetting the ECU, no CEL

 

Well I got it fixed. It did end up being the ecu pin (A4) but it wasn't that it was sliding out, it was that it was loose as a goose *****. I bit it with some pliers to make it a tighter fit and it gripped right on to that baby. Wham, bam thank you mam, no more check engine light. Thanks for the input guys.