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Home >> Jeep >> 1996 >> Grand Cherokee Limited, 5.2 Y >> Repair and Diagnosis >> External Pages >> Different car >> Section 4 (Engine Controls - Tests W/Codes - 3.0L) >> Diagnostic Charts >> Test TC-16A - Idle Air Control Motor Circuits (DTC 25)

Test TC-16A - Idle Air Control Motor Circuits (DTC 25)

WARNING: This page is about a different car, the 1994 Plymouth Sundance, 1994 Plymouth Acclaim, 1994 Dodge Spirit, 1994 Dodge Shadow, and 1994 Chrysler LeBaron. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION DIRECTORY  . For wiring diagrams, see WIRING DIAGRAMS  .
  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 6).
  2. Using DRB, set engine speed to 900 RPM. If engine speed is not 800-1000 RPM, go to step 6). If engine speed is 800-1000 RPM, go to next step.
  3. At this time, condition required to set trouble code is not present. IDLE AIR CONTROL MOTOR CIRCUITS trouble code sets if any of 4 wires are shorted to ground or to 12 volts for 2.75 seconds while IAC is active. Possible causes are: any one or more of 4 driver circuits shorted to ground, any one or more of 4 driver circuits shorted to power, any one or more of 4 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 wiring and connectors. Repair as required. Perform TEST VER-2  . If wiring and connectors are okay, start engine. Using DRB, actuate IAC wiggle test. Wiggle IAC motor wiring harness. Observe IAC motor operation.
  5. If IAC motor stopped operating at any time, repair harness or connectors as necessary. Perform TEST VER-2. If IAC motor did not stop operating at any time, stop IAC wiggle test. See INACTIVE TROUBLE CODE CONDITION  in this article. Test is complete. Perform TEST VER-2.
  6. Turn ignition off. Disconnect IAC motor connector. Inspect IAC motor connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2. If wiring and connectors are okay, go to next step.
  7. Put DRB in ohmmeter mode. Using DRB, check resistance of IAC motor connector Brown/White wire. If resistance is less than 5 ohms, repair short to ground in Brown/White wire. Perform TEST VER-2. If resistance is more than 5 ohms, go to next step.
  8. Using DRB, check resistance of IAC motor connector Yellow/Black wire. If resistance is less than 5 ohms, repair short to ground in Yellow/Black wire. Perform TEST VER-2. If resistance is more than 5 ohms, go to next step.
  9. Using DRB, check resistance of IAC motor connector Gray/Red wire. If resistance is less than 5 ohms, repair short to ground in Gray/Red wire. Perform TEST VER-2  . If resistance is more than 5 ohms, go to next step.
  10. Using DRB, check resistance of IAC motor connector Violet/Black wire. If resistance is less than 5 ohms, repair short to ground in Violet/Black wire. Perform TEST VER-2. If resistance is more than 5 ohms, go to next step.
    NOTE: Voltage may switch or remain constant during steps 11)-14).
  11. Turn ignition on. Using DRB, actuate IAC motor. Put DRB in voltmeter mode. Using DRB, check voltage on IAC motor connector Brown/White wire. If voltage is more than 5 volts at any time, go to next step. If voltage is less than 5 volts at any time, go to TEST TC-16B.
  12. Using DRB, check voltage on IAC motor connector Yellow/Black wire. If voltage is more than 5 volts at any time, go to next step. If voltage is less than 5 volts at any time, go to TEST TC-16C  .
  13. Using DRB, check voltage on IAC motor connector Gray/Red wire. If voltage is more than 5 volts at any time, go to next step. If voltage is less than 5 volts at any time, go to TEST TC-16D  .
  14. Using DRB, check voltage on IAC motor connector Violet/Black wire. If voltage is more than 5 volts at any time, go to next step. If voltage is less than 5 volts at any time, go to TEST TC-16E  .
  15. Turn ignition off. Disconnect PCM connector. Inspect PCM connector for damaged or pushed out terminals. Repair as necessary. Perform TEST VER-2. If connector is okay, go to next step.
  16. 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
  17. 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.
  18. 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
  19. 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.
  20. Using an external ohmmeter, check resistance between the following wires at IAC motor connector. Record resistance readings.
    • Gray/Red Wire And Violet/Black Wire
  21. 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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