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Home >> Jeep >> 1996 >> Cherokee Classic, Part Time, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 4.0L >> Diagnostic Trouble Code (DTC) Identification >> Test NTC-9A - Checking Idle Air Control Motor

Test NTC-9A - Checking Idle Air Control Motor

NOTE: For connector terminal identification, refer to CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.
  1. Using scan tool, set engine speed to 1100 RPM. If engine speed sets at 1050-1150 RPM, return engine to normal idle. Idle speed motor is operating properly. Test passed. If engine speed does not set as specified, return engine to normal idle and go to next step.
  2. Disconnect Idle Air Control (IAC) motor connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-2A . If connector and terminals are okay, go to next step.
  3. Using scan tool in voltmeter mode, check voltage on IAC motor connector, driver No. 1 circuit (Violet/Black wire) while momentarily opening and closing throttle. If voltage stays less than one volt, perform TEST NTC-9B . If voltage does not stay less than one volt, go to next step.
  4. Check voltage on IAC motor connector, driver No. 2 circuit (Brown/White wire) while momentarily opening and closing throttle. If voltage stays less than one volt, perform TEST NTC-9B . If voltage does not stay less than one volt, go to next step.
  5. Check voltage on IAC motor connector, driver No. 3 circuit (Yellow/Black wire) while momentarily opening and closing throttle. If voltage stays less than one volt, perform TEST NTC-9B . If voltage does not stay less than one volt, go to next step.
  6. Check voltage on IAC motor connector, driver No. 4 circuit (Gray/Red wire) while momentarily opening and closing throttle. If voltage stays less than one volt, perform TEST NTC-9B . If voltage does not stay less than one volt, go to next step.
  7. Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST VER-2A . If connectors and terminals are okay, go to next step.
    NOTE: Steps 8)-11) check for short circuits between IAC motor driver circuits.
  8. Using an external ohmmeter, check resistance between IAC motor connector, driver No. 1 circuit (Violet/Black wire) and each remaining circuit on IAC motor connector. If resistance is less than 5 ohms between any 2 circuits, repair driver circuits that are shorted together and perform TEST VER-2A . If resistance is 5 ohms or more on all IAC motor driver circuits, go to next step.
  9. Check resistance between IAC motor connector, driver No. 2 circuit (Brown/White wire) and each remaining circuit on IAC motor connector. If resistance less than 5 ohms between any 2 circuits, repair driver circuits shorted together and perform TEST VER-2A. If resistance is 5 ohms or more on all IAC motor driver circuits, go to next step.
  10. Check resistance between IAC motor connector, driver No. 3 circuit (Yellow/Black wire) and each remaining circuit on IAC motor connector. If resistance is less than 5 ohms between any 2 circuits, repair driver circuits that are shorted together and perform TEST VER-2A. If resistance is 5 ohms or more on all IAC motor driver circuits, go to next step.
  11. Check resistance between IAC motor connector, driver No. 4 circuit (Gray/Red wire) and each remaining circuit on IAC motor connector. If resistance less than 5 ohms between any 2 circuits, repair driver circuits shorted together and perform TEST VER-2A. If resistance 5 ohms or more replace IAC motor and perform TEST VER-2A .
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