To start off please don’t tell me to use the search button because I have tried searching this everywhere and have not been able to find a solution that works for my case. My dad has a jdm b18c5 and we have had a problem where the vtec will not disengage after engaging, the only solution is the turn the car off then back on. I do know that the USDM and JDM b18c5 have differences because the JDM one dosent have a VTEC pressure censor so using a USDM ecu can cause vtec to not disengage, but I did confirm he is using the matching JDM ecu so that is not the problem. I know he has tried fixing it many times and tried searching for a solution online in different forums with no luck. If anyone has any information on a solution it would be a huge help, thanks! I will try and get more information on what has been done to try and fix it.

 

What makes you think that VTEC is staying engaged once it has clicked on ? I have seen, heard, and even read about VTEC NOT engaging in the first place... for various reasons... but never that it won't "turn off" once it has been turned on.

 

first do some basic troubleshooting,

1. unplug the VTEC solenoid and drive it to see what happens. this will tell you if there is something internally turning on the solenoid.
if VTEC still turns on and/or stays on, then the solenoid needs to be replaced or cleaned. (usually this causes it to not turn on though)
if it does nothing, plug in solenoid and #2

2. unplug the wire at the ECU and drive it. same as above but now you've eliminated the ECU and not anything else that could be connected to the solenoid wire.
if VTEC works and/or stays on like before, check for anything that should not be connected to that wire.
if it does nothing, plug back in wire and #3

3. connect a Volt meter to the VTEC solenoid wire and see what it does. it should be a solid battery voltage when on and <0.5v when off. anything in between you may have an ECU problem or again a miss connection problem somewhere in the wiring.
if it works normally, disconnect meter and #4

4. disconnect the VTEC Wire at the solenoid and connect a switch to it. on is 12v, off is open. drive the car and turn on the switch... VTEC should be noticeable when you turn on and off the switch. if it feels like it remains on, replace the VTEC solenoid.
if it follows the switch, remove switch and wire, plug back in normally and #5

5. replace the ECU.


as JRCivic1 said, staying on is not a common problem, nor one that I've ever heard of. It's a very simple circuit, there isn't a lot to go wrong in the on-to-off direction.

 

Well stated Relic1... great job.

 

thanks so much for the help i will be sure to try all of these