Right were do I start.
Had my h2b tuned ran fine and strong now VTEC has stopped working and I get code 21 so far I've done.
Replaced all wires and plugs .all gaskets . Changed the oil. Tested and even jumped the VTEC pressure switch all fine. Tested vss and coolant temp sensor. Put a new o ring under the center cam holder that provides oil to the VTEC switch .going to test my ecu on a friend's h2b after that fit a oil pressure gauge to see if the oil pump has gone bad.

Any one else got any ideas