Swift DOHC

1. Warm engine to normal operating temperature. With engine running, use stethoscope and check for operating sound at ISC solenoid. ISC solenoid is mounted on intake manifold, between valve covers.
2. If operating sound is hear, go to step 4). If no operating sound is hear, check ISC solenoid. See IDLE SPEED CONTROL (ISC) SOLENOID  under IDLE CONTROL SYSTEM. Replace ISC solenoid if defective. If ISC solenoid is okay, go to next step.
3. Check for open or short in Red/White wire between ECM and ISC solenoid. Check for defective connection at ISC solenoid and ECM. If wiring and connections are okay, substitute ECM and recheck.
4. With engine idling, pinch upper hose on ISC solenoid closed. Note if engine speed decreases. If engine speed decreases, go to step 5). If engine speed dose not decrease, check for restricted air passages on ISC solenoid.
5. Ensure idle speed is within specification. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. With idle speed correct, ensure the following conditions are present:
   • Idle speed remains at 800-900 RPM with headlights on.
   • Ensure ISC solenoid dose not operate (operating sound is not heard) for only a few seconds after warm engine is started.
   • Increase engine speed to 4000 RPM, quickly close throttle valve and ensure ISC solenoid does not operate (Operating sound is not heard) for only a few seconds.

If all conditions are met, system is operating correctly. If all conditions are not met, substitute a known good ECM and recheck.