Mazda MX-5 NA silhouetteMX-5 NA

IDLE SPEED CONTROL (ISC) SYSTEM

F-99prose procedure
Continued from F-98

Inspection

Air Valve Inspection

  1. 1
    Cool the air valve to 0°C (31°F).
  2. 2
    Mark the shaft.
    Air valve component shown with an arrow indicating shaft movement direction. Callout 'SHAFT' identifies the shaft to mark during the cold inspection.
    05U0FX-124
  3. 3
    Warm the air valve with a hot air gun and verify that the shaft moves in the direction of arrow.
  4. 4
    Replace the air valve if necessary.

Installation

Install in the reverse order of removal.
Air valve
4.9 - 7.8N·m

ISC VALVE

Inspection

ISC Valve Inspection

  1. 1
    Disconnect the ISC valve connector.
    Engine bay photograph showing the ISC valve with its connector being disconnected for ohmmeter resistance measurement.
    05U0FX-126
  2. 2
    Connect an ohmmeter between the terminals of the ISC valve and measure the resistance.
  3. 3
    If not as specified, replace the ISC valve.
Resistanceat 20°C [68°F]
12 ± 1Ω

Replacement

ISC Valve Replacement

  1. 1
    Disconnect the ISC valve connector.
  2. 2
    Remove the air pipe.
    Before disconnecting the water hose, drain the engine coolant.
    Engine bay photograph showing the ISC valve replacement area — the air pipe being removed and the ISC valve hose/air-hose connections.
    05U0FX-127
  3. 3
    Disconnect the water hose and the air hose.
  4. 4
    Remove the ISC valve.
    Close-up photograph of the throttle body / ISC valve mounting area after removal of the ISC valve.
    05U0FX-128
  5. 5
    Install in the reverse order of removal.
    Install a new gasket.
ISC valve
2.8 - 4.0N·m
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