i also have a 1990 toyota pickup where i can stick a pair of pliars in the diagnostic port and it flashes the check light so many times. i was wondering if i could do the same thing to the highlander and where i would put the pliars.

Get a code reader if you start jamming things in the reader port you may short out the ECU unit and then your talking big money to replace it.you can buy cheap code reader that will work