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Home >> Isuzu >> 1993 >> Stylus Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - EFI >> Idle Control System >> Chart C-2C - Idle Air Control Valve >> Notes
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Chart C-2C - Idle Air Control Valve: Notes

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. IAC tester is used to extend and retract IAC valve. Valve movement is verified by engine speed change. If engine speed does not change, valve can be retested when removed from throttle body.
  2. This step check quality of IAC movement in step 1). Engine speed should change smoothly with each flash of tester light in both extend and retract positions at 700-1500 RPM. If IAC valve is retracted beyond control range (1500 RPM), it may take many flashes in extend position before engine speed will begin to drop. Fully extending IAC valve may stall engine. This is normal condition.
  3. Steps 1) and 2) verify proper IAC valve operation. This step checks IAC circuits. Each lamp on node light should flash Red and Green while IAC valve is cycled. While sequence of color is not important, check circuits for faults if either light is off or does not flash. Begin with poor terminal connections.
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