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Test NTC-12A: Checking Idle Air Control Motor

NOTE: This test does not apply to AB body. For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Start engine and allow it to reach normal operating temperature. Using scan tool, set engine speed to 1400 RPM. If engine speed sets at 1300-1500 RPM, return engine to normal idle. Idle speed motor is operating properly. Test passed. If engine speed does not set as specified, use scan tool to return engine to normal idle and go to next step.
  2. Using scan tool, stop all actuation tests. Inspect engine for vacuum leaks. Repair vacuum leaks as necessary and perform TEST VER-2A: ROAD TEST VERIFICATION . If no vacuum leaks exist, go to next step.
  3. Turn engine off. Disconnect Idle Air Control (IAC) motor connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-2A: ROAD TEST VERIFICATION . If connector and terminals are okay, go to next step.
  4. Using an external ohmmeter, check resistance between ground and IAC motor connector, driver No. 1 circuit (Gray/Red wire). If resistance is less than 5 ohms, repair driver circuit for short to ground and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or more, go to next step.
  5. Check resistance between ground and IAC motor connector, driver No. 2 circuit (Yellow/Black wire). If resistance is less than 5 ohms, repair driver circuit for short to ground and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or, go to next step.
  6. Check resistance between ground and IAC motor connector, driver No. 3 circuit (Brown/White wire). If resistance is less than 5 ohms, repair driver circuit for short to ground and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or more, go to next step.
  7. Check resistance between ground and IAC motor connector, driver No. 4 circuit (Violet/Black wire). If resistance is less than 5 ohms, repair driver circuit for short to ground and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or more go to next step.
    NOTE: Voltage may switch or remain constant in following tests.
  8. Turn ignition on. Using scan tool, select actuator tests. Select stepper motor. Go to next step.
  9. Using scan tool in voltmeter mode, check voltage on IAC motor connector, driver No. 1 circuit (Gray/Red wire). If voltage is more than 10 volts at any time, perform TEST TC-25B: IDLE AIR CONTROL MOTOR CIRCUITS . If voltage is not more than 10 volts at any time, go to next step.
  10. Check voltage on IAC motor connector, driver No. 2 circuit (Yellow/Black wire on all other bodies). If voltage is more than 10 volts at any time, perform TEST TC-25C: IDLE AIR CONTROL MOTOR CIRCUITS . If voltage is not more than 10 volts at any time, go to next step.
  11. Check voltage on IAC motor connector, driver No. 3 circuit (Brown/White wire). If voltage is more than 10 volts at any time, perform TEST TC-25D: IDLE AIR CONTROL MOTOR CIRCUITS . If voltage is not more than 10 volts at any time, go to next step.
  12. Check voltage on IAC motor connector, driver No. 4 circuit (Violet/Black wire). If voltage is more than 10 volts at any time, perform TEST TC-25E: IDLE AIR CONTROL MOTOR CIRCUITS . If voltage is not more than 10 volts at any time, Perform TEST NTC-12B: CHECKING IDLE AIR CONTROL MOTOR .
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