Narrative:

Aircraft X on a VFR route requested to be routed to the east enroute to [their destination]. I advised aircraft X to pass north of the bridge toll plaza and remain north of class C airspace and the pilot acknowledged. A few moments later; aircraft X turn southeast bound and began descending; then asked if he could transition over the airspace in class C. I approved the transition while instructing aircraft X to climb to 2;500 feet for traffic; and then quoted the opposite direction traffic. Aircraft X acknowledged and said he was looking for the traffic. I wasn't satisfied with the climb rate of aircraft X; so I vectored the aircraft southbound; and asked my coordinator to advise tower; who had the handoff at this point; what I was doing. After some coordination; the coordinator told me tower wanted me to stop aircraft X's climb at 1;500 feet; which I promptly did. Aircraft X was leaving a MVA (minimum vectoring altitude) area of 3;000 feet into 1;700 feet followed shortly by 2;800 feet. Between the last 2 transmissions; I had aircraft X on a vector below the MVA and an assigned altitude below the MVA.my plan to vector aircraft X and leave him climbing was a good plan. Once past the traffic; resuming own navigation I mistakenly heeded the advice of tower to stop the climb of aircraft X at an altitude below the MVA; while still on a vector. I take responsibility for this action; and will have more confidence in my plan in the future. Additionally; because of the speed of aircraft X and his proximity to class C; I should have disapproved his request due to traffic in the area.

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Original NASA ASRS Text

Title: NCT TRACON Controller reported assigning a vector and heading to a VFR aircraft below the MVA.

Narrative: Aircraft X on a VFR route requested to be routed to the east enroute to [their destination]. I advised Aircraft X to pass north of the Bridge Toll Plaza and remain north of Class C airspace and the pilot acknowledged. A few moments later; Aircraft X turn southeast bound and began descending; then asked if he could transition over the airspace in Class C. I approved the transition while instructing Aircraft X to climb to 2;500 feet for traffic; and then quoted the opposite direction traffic. Aircraft X acknowledged and said he was looking for the traffic. I wasn't satisfied with the climb rate of Aircraft X; so I vectored the aircraft southbound; and asked my coordinator to advise Tower; who had the handoff at this point; what I was doing. After some coordination; the coordinator told me Tower wanted me to stop Aircraft X's climb at 1;500 feet; which I promptly did. Aircraft X was leaving a MVA (Minimum Vectoring Altitude) area of 3;000 feet into 1;700 feet followed shortly by 2;800 feet. Between the last 2 transmissions; I had Aircraft X on a vector below the MVA and an assigned altitude below the MVA.My plan to vector Aircraft X and leave him climbing was a good plan. Once past the traffic; resuming own navigation I mistakenly heeded the advice of Tower to stop the climb of Aircraft X at an altitude below the MVA; while still on a vector. I take responsibility for this action; and will have more confidence in my plan in the future. Additionally; because of the speed of Aircraft X and his proximity to Class C; I should have disapproved his request due to traffic in the area.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.