My friends been having some wierd troubles with his vtec lately, heres whats going on.

it will drive fine, and goes into vtec like a good engine, but then without warning the check engine light comes on and the vtec will no longer engauge....
If he unhooks his battery for a minute the vtec will work again. He tried replaceing the vtec controller but still the same problem. i remember a forum about someones vtec getting dirty? like a clogged filter or something? i'm not exactly sure about how the vtec solenoid works but could this be the problem?


thanks