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Home >> Suzuki >> 1995 >> Sidekick JS, 4D Utility, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - TBI >> Idle Control System >> Idle Air Control (IAC)
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Idle Air Control (IAC)

  1. Before idle speed/IAC duty is checked or adjusted, ensure all wires and vacuum hoses are connected securely, accelerator cable has some play, valve clearance and timing are set to specification, and all accessories are turned off.
  2. Warm engine to normal operating temperature. Connect a jumper wire between terminals "C" (ground) and "B" (diagnostic terminal) of test connector. Test terminal is located next to battery. See Fig 1 . Observe Malfunction Indicator Light (MIL). If Code 12 flashes, proceed to next step. If Code 12 does not flash, see appropriate Initial Diagnostic Procedure chart (Chart A-1, A-2 or A-3) in the TESTS W/CODES - TBI article.
    Fig 1: IAC Solenoid Wiring Schematic (Typical)
    G94I45201Courtesy of SUZUKI OF AMERICA CORP.
  3. Stop engine and connect duty meter between terminals "A" (output) and "C" (ground). Check IAC duty and idle speed. If IAC duty and idle speed are correct, system is functioning properly. If idle speed is too high, go to next step. If idle speed is too low, go to step 6).
  4. If idle speed is too high, check IAC solenoid valve resistance. If reading is not 11-14 ohms at 68°F (20°C), replace solenoid valve. If resistance is 11-14 ohms, observe duty meter. Duty meter values are relative to battery voltage. Off-duty indication percentage at zero voltage would be 100 percent and zero percent at highest battery voltage. Off-duty value should be more than 72 percent. If off-duty value is not as specified, check Light Green/Black wire for short to ground. If Light Green/Black wire is okay, substitute a known-good ECM and recheck.
  5. If off-duty value is as specified, ensure intake system is free of vacuum leaks. Repair or replace as necessary. Adjust duty and idle to specification by turning idle adjusting screw. If not adjustable, check Fast Idle Air (FIA) valve for leakage. Repair or replace as necessary.
  6. If idle speed is too low, check IAC solenoid valve resistance. If reading is not 11-14 ohms at 68°F (20°C), replace solenoid valve. If resistance is 11-14 ohms, observe duty meter. Duty values are relative to battery voltage. Off-duty percentage at zero voltage would be 100 percent, and zero percent at highest battery voltage. Off-duty value should be about zero percent. On-duty reading would be about 100 percent.
  7. If reading is not as specified, adjust by turning idle speed screw. Refer to IDLE SPEED under IGNITION TIMING in the ADJUSTMENTS article. After making adjustments, remove jumper wire and replace protective caps (if equipped). Recheck idle speed with A/C on. See the ADJUSTMENTS article. If reading is as specified, check for clogged IAC hose, open in Light Green/Black wire or poor connector connections. Repair or replace as necessary. If all are okay, substitute a known-good ECM and recheck.
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