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HOMESERVICE MANUALSPLYMOUTH1994GRAND VOYAGER BASE, 31THREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - TESTS W/CODES - 2.5L TBISELF-DIAGNOSTIC TESTSTEST TC-12A - IDLE AIR CONTROL MOTOR CIRCUITS (DTC 25)
1994 Plymouth Grand Voyager Base, 31TH

Test TC-12A - Idle Air Control Motor Circuits (DTC 25)

1994 Plymouth Grand Voyager Base, 31THSECTION Test TC-12A - Idle Air Control Motor Circuits (DTC 25)
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION  in this article. For wiring diagrams, see WIRING DIAGRAMS  section.
  1. Turn engine off. Turn ignition on. Start engine. Allow engine to idle for 20 seconds. Using DRB, set engine speed 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 DRB, reset engine speed 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 required to set trouble code is not present at this time. The IDLE AIR CONTROL MOTOR CIRCUITS trouble code sets if any of the 4 Idle Air Control (IAC) motor wires are shorted to ground or battery voltage. Go to next step.
  4. Inspect all related wiring and connectors and repair as necessary. Perform TEST VER-2  . If no problems were found with wiring and connectors, start engine. Run engine until operating temperature is reached.
  5. Using DRB, actuate IAC wiggle test. Idle speed should raise and lower slowly with DRB display. If IAC motor operated properly, go to next step. If IAC motor did not operate properly, go to step 7).
  6. Stop IAC wiggle test. If IAC wiggle test functioned properly, see INACTIVE TROUBLE CODE CONDITION  in this article. Perform TEST VER-2.
  7. Turn ignition off. Disconnect Idle Air Control (IAC) motor connector. Inspect IAC motor connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2. If IAC motor connector terminals are okay, put DRB in ohmmeter mode.
  8. Using DRB, check resistance of IAC connector Brown/White wire. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Brown/White wire. Perform TEST VER-2.
  9. Using DRB, check resistance of IAC connector Yellow/Black wire. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Yellow/Black wire. Perform TEST VER-2  .
  10. Using DRB, check resistance of IAC connector Gray/Red wire. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Gray/Red wire. Perform TEST VER-2.
  11. Using DRB, check resistance of IAC connector Violet/Black wire. If resistance is more than 5 ohms, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/Black wire. Perform TEST VER-2.
    NOTE: While measuring voltage in steps 12)-15), voltage may switch or remain constant.
  12. Using DRB, actuate IAC motor. Using DRB in voltmeter mode, check voltage of IAC connector Brown/White wire. If voltage is more than 5 volts at any time, go to next step. If voltage was not more than 5 volts at any time, go to TEST TC-12B.
  13. Using DRB, check voltage of IAC connector Yellow/Black wire. If voltage is more than 5 volts at any time, go to next step. If voltage was not more than 5 volts at any time, go to TEST TC-12C  .
  14. Using DRB, check voltage of IAC connector Gray/Red wire. If voltage is more than 5 volts at any time, go to next step. If voltage was not more than 5 volts at any time, go to TEST TC-12D  .
  15. Using DRB, check voltage of IAC connector Violet/Black wire. If voltage is more than 5 volts at any time, go to next step. If voltage was not more than 5 volts at any time, go to TEST TC-12E  .
  16. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2  . If PCM connector terminals are okay, go to next step.
  17. Disconnect Powertrain Control Module (PCM) connector. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • Brown/White Wire And Yellow/Black Wire
    • Brown/White Wire And Gray/Red Wire
    • Brown/White Wire And Violet/Black Wire
  18. If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2. If resistance between all pairs of wires was more than 5 ohms, go to next step.
  19. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • Yellow/Black Wire And Gray/Red Wire
    • Yellow/Black Wire And Violet/Black Wire
  20. If resistance between any 2 wires was less than 5 ohms, repair those wires for shorting together. Perform TEST VER-2. If resistance between all pairs of wires was more than 5 ohms, go to next step.
  21. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • Gray/Red Wire And Violet/Black Wire
  22. If resistance between wires was less than 5 ohms, repair wires for shorting together. Perform TEST VER-2. If resistance between wires was more than 5 ohms, replace IAC motor. Perform TEST VER-2.
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