Had a customer with a GSR complaining that VTEC was not working. Checked the oil-it was full. Drove the car-yup, no VTEC. No codes stored in ECU. Had me scratching my head. Checked wiring from ECU to VTEC solenoid and VTEC pressure solenoid. All o.k.
Pulled off the VTEC solenoid and found the problem. The little screen in the rubber o-ring was plugged with gunk. Cleaned the screen and changed the oil and the VTEC was back online. Just thought I'd share.

 

good stuff