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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Idle Control System >> Idle Air Control Valve System Check >> Vitara
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Idle Air Control Valve System Check: Vitara

  1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See IDLE SPEED & MIXTURE . If idle speed is within specification, go to next step. If idle speed is not as specified, go to step  3 .
  2. Turn headlights on. If idle speed stays within specifications, system is okay. If idle speed drops below specification, go to next step.
  3. Check IAC valve operation. See IDLE AIR CONTROL VALVE  . If no problem is found, go to next step. If problem is found, check wire harness for open, short or poor coupler connections. If check is OK, substitute a known-good ECM (PCM) and recheck IAC valve operation.
  4. If idle speed was not within specification in step  1 , go to next step. If idle speed was within specification in step  1 , check for the following:
    • Vacuum leaks.
    • Air inhailing.
    • EVAP system malfunction.
    • High accessory engine load.
    • PCV system malfunction.
    • Clogged idle air passage.
    • MAF sensor malfunction.
    • Throttle position sensor malfunction.
    • Engine coolant temperature sensor malfunction.
    • EGR valve malfunction.
    • A/C signal malfunction.
    • Transmission range switch signal malfunction.
  5. If idle speed was higher than specification in step  1 , go to next step. If not, go to step  9 .
  6. Check A/C input signal to ECM. See A/C SIGNALS CIRCUIT CHECK  under MISCELLANEOUS CONTROLS. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
  7. Turn ignition switch ON and check voltage between ECM connector E61 terminal No. 30 and body ground. See Figure . If voltage is 10-14 volts, go to next step. If voltage is not within specification, ABS signal circuit shorted to ground or ABS malfunction.
  8. If IAC duty was less than about 2% in step  1 , check for abnormal air inhaling from intake manifold, throttle body, PCV valve and EVAP canister purge control system. If IAC duty was not less than 2% in step  1 , check throttle position sensor and ECT sensor for performance. If sensors are OK, substitute a known-good ECM (PCM) and recheck.
  9. Check transmission range switch signal. See TRANSMISSION RANGE SENSOR  . If check results are satisfactory, go to next step. If results are not satisfactory, transmission range switch is malfunctioning or its circuits are open or short.
  10. If IAC duty was more than about 30% in step  1 , check parts or systems that can cause engine low idle. If IAC duty was not more then 30% in step  1 , substitute a known-good ECM (PCM) and recheck.
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