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Idle Speed Control (ISC) System: Turbo

  1. Warm engine to normal operating temperature. Ensure idle speed is correct. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. Apply parking brake and place transaxle in Neutral.
  2. Disconnect electrical connector from ISC valve. Engine RPM should increase at least 1000 RPM. Reinstall electrical connector on ISC valve.
  3. Ensure engine returns to idle speed of 750-850 RPM. If engine does not return to proper idle speed, check ISC valve, wiring to ECU, ECU grounds and ECU.
  4. To check ISC valve resistance, disconnect electrical connector from ISC valve. Using ohmmeter, measure resistance between terminal B+ and each remaining terminal. See Figure and Figure .
  5. Replace ISC valve if resistance is not within specification. See ISC VALVE RESISTANCE SPECIFICATIONS table. To check ISC valve operation, remove ISC valve. Connect battery to proper terminals and ensure valve opens and closes. See Figure-Figure . Replace ISC valve if defective.
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