2004 Honda Civic SiFACTORY OEM SERVICE PROCEDURE

Idle Speed Inspection

NOTE: Leave the idle air control (IAC) valve connected. Before checking the idle speed, check these items:
  • The malfunction indicator lamp (MIL) has not been reported on.
  • Ignition timing
  • Spark plugs
  • Air cleaner
  • PCV system

Pull the parking brake lever up. Start the engine, and make sure the headlights are off.

  1. Disconnect the evaporative emission (EVAP) canister purge valve 2P connector.
  2. Connect a tachometer (A) to the test tachometer connector (B), or connect the HDS or a scan tool to the data link connector (DLC) (C) located under the driver's side of the dashboard.
    Fig 1: Connecting A Tachometer To The Test Tachometer Connector, Or Connecting The HDS Or A Scan Tool To The Data Link Connector (DLC) Located Under The Driver's Side Of The Dashboard
    G01399540Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. Start the engine. Hold the engine at 3,000 RPM with no load (in neutral) until the radiator fan comes on, then let it idle.
  4. Check the idle speed with no-load conditions: headlights, blower fan, and radiator fan, and air conditioner off.
    1. Idle Speed Should Be:  750 plus or minus 50 RPM
  5. Let the engine idle for 1 minute with the heater fan switch on HI and air conditioner on, then check the idle speed.
    1. Idle Speed Should Be:  750 plus or minus 50 RPM
    NOTE: If the idle speed is not within specification, go to the Symptom Troubleshooting.
  6. Reconnect the EVAP canister purge valve 2P connector.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.