LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Eagle >> 1996 >> Talon Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Non-Turbo >> Trouble Code Tests >> Test TC-25A - Idle Air Control Motor Circuits
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test TC-25A - Idle Air Control Motor Circuits

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION  Directory. For wiring diagram, see WIRING DIAGRAMS article.
  1. Turn ignition off for 10 seconds. Start engine. Allow engine to idle for 20 seconds. Using scan tool, actuate Idle Air Control (IAC) motor to 1400 RPM. If engine speed is 1300-1500 RPM, go to next step. If engine speed is not 1300-1500 RPM, go to step 7).
  2. Using scan tool, actuate IAC motor to 900 RPM. If engine speed is 800-1000 RPM, go to next step. If engine speed is not 800-1000 RPM, go to step 7).
  3. Condition to set trouble code is not present at this time. IDLE AIR CONTROL MOTOR CIRCUITS DTC sets if Power Control Module (PCM) senses a short to ground or battery voltage on any 4 IAC driver circuits for 2.75 seconds while IAC motor is active. Possible causes are: driver circuit shorted to ground, driver circuit shorted to battery, driver circuits shorted together, failed PCM or shorted IAC motor. PCM cannot detect an open driver circuit or a stuck IAC motor. Go to next step.
  4. Inspect all related wiring and connectors and repair as necessary. If no problems were found with wiring and connectors, go to next step. If related wiring and connectors were repaired, perform TEST VER-2A.
  5. Start engine. Allow engine to run until operating temperature is reached. Using scan tool, actuate IAC motor wiggle test. Idle speed should raise and lower with scan tool display. If IAC motor operates properly, go to next step. If IAC motor does not operate properly, go to step 7).
  6. Wiggle wiring harness from IAC motor to Powertrain Control Motor (PCM). If IAC motor stopped operating at any time, repair wiring harness as necessary where wiggling caused problem to appear. Perform TEST VER-2A. If IAC motor did not stop operating at any time, stop IAC motor wiggle test. See INACTIVE TROUBLE CODE CONDITION . Test is complete. Perform TEST VER-2A.
    NOTE: For test steps 7-11), see IAC DRIVER IDENTIFICATION table for IAC motor wire color identification.
    IAC DRIVER IDENTIFICATION

    Application Wire Color
    Driver No. 1 Dark Green
    Driver No. 2 Orange
    Driver No. 3 Dark Green/Dark Blue
    Driver No. 4 Yellow/Dark Blue
  7. Turn ignition off. Disconnect IAC motor connector. Inspect IAC motor connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2A. If wiring and connectors are okay, go to next step.
  8. Using scan tool in ohmmeter mode, check resistance of IAC motor connector driver No. 1 wire. If resistance is less than 5 ohms, repair short to ground in driver No. 1 wire. Perform TEST VER-2A. If resistance is more than 5 ohms, go to next step.
  9. Using scan tool, check resistance of IAC motor connector driver No. 2 wire. If resistance is less than 5 ohms, repair short to ground in driver No. 2 wire. Perform TEST VER-2A. If resistance is more than 5 ohms, go to next step.
  10. Using scan tool, check resistance of IAC motor connector driver No. 3 wire. If resistance is less than 5 ohms, repair short to ground in driver No. 3 wire. Perform TEST VER-2A. If resistance is more than 5 ohms, go to next step.
  11. Using scan tool, check resistance of IAC motor connector driver No. 4 wire. If resistance is less than 5 ohms, repair short to ground in driver No. 4 wire. Perform TEST VER-2A. If resistance is more than 5 ohms, go to next step.
    NOTE: Voltage may switch or remain constant during steps 12-15).
  12. Turn ignition on. Using scan tool, actuate IAC motor. Using scan tool in voltmeter mode, check voltage on IAC motor connector driver No. 1 wire. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25B.
  13. Using scan tool, check voltage on IAC motor connector driver No. 2 wire. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25C.
  14. Using scan tool, check voltage on IAC motor connector driver No. 3 wire. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25D.
  15. Using scan tool, check voltage on IAC motor connector driver No. 4 wire. If voltage is more than 5 volts at any time, go to next step. If voltage is 5 volts or less at any time, go to TEST TC-25E.
  16. Turn ignition off. Disconnect PCM connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2A. If connector is okay, go to next step.
  17. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • IAC motor connector driver No. 1 and driver No. 2
    • IAC motor connector driver No. 1 and driver No. 3
    • IAC motor connector driver No. 1 and driver No. 4
  18. If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2A. If resistance between all pairs of wires was 5 ohms or more, go to next step.
  19. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • IAC motor connector driver No. 2 and driver No. 3
    • IAC motor connector driver No. 2 and driver No. 4
  20. If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2A. If resistance between all pairs of wires was 5 ohms or more, go to next step.
  21. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • IAC motor connector driver No. 3 and driver No. 4
  22. If resistance between wires was less than 5 ohms, repair wires for shorting together. Perform TEST VER-2A. If resistance between wires was 5 ohms or more, replace IAC motor. Perform TEST VER-2A.
scientia non olet · About LEMON Manuals