Idle Speed Control Solenoid & Wiring Circuit
- With ignition off, disconnect electrical connector from Idle Speed Control (ISC) solenoid. The ISC solenoid is located on right side of throttle body and contains a Blue/Black and Light Green/Black wire connector.
- Turn ignition on. Using voltmeter, check for battery voltage at Blue/Black wire of electrical connector. Battery voltage should exists.
- If battery voltage exits, proceed to step 4). If battery voltage does not exist, check for open circuit in Blue/Black wire between ISC solenoid and EFI main relay. The EFI main relay is mounted on the ECM, located under left side of instrument panel, near kick panel. See Figure .
- Turn ignition off. Connect test light to battery voltage and probe Light Green/Black wire. Turn ignition on. Test light should come on momentarily.
- If test light comes on momentarily, proceed to step 6). If test light stays on, check for short to ground in Light Green wire between ISC solenoid and ECM. If test light does not come on momentarily, check for open circuit in Light Green wire between ISC solenoid and ECM. The ECM is located under left side of instrument panel, near kick panel. See Figure . If no open circuit exists, replace ECM.
- Turn ignition off. Using ohmmeter, measure resistance between ISC solenoid terminals. Resistance should be 11-14 ohms at 68°F (20°C).
- If resistance is not within specification, replace ISC solenoid. If resistance is within specification, connect battery voltage to Blue/Black wire terminal and ground Light Green wire terminals momentarily. A "click" sound should be heard to indicate solenoid operation. Replace ISC solenoid if it did not operate. Reinstall electrical connector.
CAUTION:
DO NOT apply battery voltage to ISC solenoid for more than one second and allow 10 seconds between voltage applications to prevent solenoid damage.
NOTE:
The idle-up vacuum switching valve also may be referred to as the Idle Speed Control (ISC) solenoid.