Check the voltage at the idle control valve by backprobing the harness with a multi meter set to dc volts should read around 4 volts. if nothing check continuity of the black and yellow wire from the idle valve to the idle control unit using multi meter set to ohms should read open. check the black wire in the same way. if the resistance is infinite find and repair the break in the wire. if ok check for voltage on the red and blue wire in the harness at the idle control unit behind the glove box remove the lower cover and the inner cover of the glove box to gain access. if no voltage strip the covering on the red and blue and use a jumper to energize the wire from the fuse block. if this solves the problem trace the red and blue wire back to the overvoltage protection relay and check the function of the relay.