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Home >> Suzuki >> 2006 >> Swift + >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - 1.6L (L91) - DTC P0420 To DTC P2076 >> DTC P0506 or P0507 w/o Throttle Actuator Control >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector of the IAC valve.
  2. Connect the J 37027-A to the IAC valve.
  3. Engine running, command the IAC valve in until 600 RPM is reached with the J 37027-A , then command the IAC valve out until 1,800 RPM is reached then lower the idle to 800 RPM. The engine speed should steadily increase and decrease as commanded.
    • If the idle does not increase or decrease steadily, verify that one of the following conditions is not present:
      • A clogged IAC passage
      • Excessive deposits on the throttle plate or bore
      • Excessive deposits on IAC valve pintle or bore
      • Restricted air intake system
      • The throttle body for damage and/or tampering
      • Vacuum leaks
      • Malfunctioning PCV valve
    • If all conditions test normal, test or replace the IAC valve.
  4. Connect a test lamp between the IAC coil A high control circuit and ground.
    5. IMPORTANT: This test must be performed on all of the IAC control circuits.
  5. Engine running, command the IAC valve out until 1,800 RPM is reached then lower the idle to 800 RPM with the J 37027-A . The test lamp should flash.
    • If the test lamp does not illuminate, test the applicable IAC control circuit of the IAC valve for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
    • If the test lamp does illuminate, but does not flash, test the applicable IAC control circuit of the IAC valve for a short to voltage. If the circuit/connections test normal, replace the ECM.
    • If test lamp illuminates and flashes for all of the IAC control circuits, test the IAC coil control circuits of the IAC valve for high resistance. If the circuit/connections test normal, replace the ECM.
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