Diagnostic Aids
Use scan tool to monitor IAC MOTOR CKT. - LOW VOLT test while accelerating engine between idle and 3500 RPM. When a fault exists, scan tool will display TEST FAIL. Test updates every 100 milliseconds when IAC valve is commanded to move.
Moving valve in one direction with scan tool will allow current to flow through both coils and polarity to flip on both coils as well.
IAC terminal resistance between terminals "A" to "B" and "C" to "D" should be 40-80 ohms. All other terminal combinations should be infinite (open).