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Home >> Dodge and Ram >> 1998 >> Caravan Base, 2.4 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.4L >> DTC Test >> Test TC-25A - Idle Air Control Motor Circuits

Test TC-25A - Idle Air Control Motor Circuits

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.
  1. Start engine and allow engine to warm to normal operating temperature. Turn ignition off. Ensure ignition is off for at least 10 seconds. Start engine and allow engine to idle. Ensure engine is at normal operating temperature.
  2. Using scan tool, actuate idle air control motor to 1400 RPM. Note if engine speed is 1300-1500 RPM. If engine speed is not within specification, go to step  10. If engine speed is within specification, go to next step.
  3. Using scan tool, actuate idle air control motor to 900 RPM. Note if engine speed is 800-1000 RPM. If engine speed is not within specification, go to step  10. If engine speed is within specification, go to next step.
  4. Actuate STOP ALL TESTS on scan tool. Go to SYSTEM TESTS on scan tool. Perform IAC WIGGLE test. Idle speed should increase and then decrease in accordance with display on scan tool if idle air control motor is operating correctly. If idle air control motor is operates correctly, go to next step. If idle air control motor is not operating correctly, go to step  10.
  5. Wiggle wiring harness from idle air control motor to the Powertrain Control Module (PCM) while observing operation of idle air control motor. Idle air control motor is mounted on the throttle body and contains a 4-pin connector. The PCM is located between driver's side front fender and power distribution center, near battery.
  6. If idle air control motor does not stop operating while wiggling wiring harness, go to next step. If idle air control motor stops operating at any time while wiggling wiring harness, repair wiring harness and connectors as necessary. Perform TEST VER-2A - ROAD TEST VERIFICATION .
  7. Stop IAC WIGGLE test. Turn engine off. Check for defective wiring or connections at idle air control motor and PCM. If no defective wiring or connections exist, go to next step. If defective wiring or connections exist, repair as necessary. Perform TEST VER-2A - ROAD TEST VERIFICATION .
  8. Conditions required to set DTC are not present at this time. The PCM uses idle air control motor for controlling idle speed. Idle air control motor controls the amount of air by-passing the throttle blade. DTC may be stored in PCM if PCM senses a short to ground or battery voltage on any of the 4 idle air control motor driver circuits while idle air control motor is operating.
  9. Possible causes are: driver circuit shorted to ground or battery voltage, driver circuits shorted together, defective PCM, shorted idle air control motor, defective connector terminals or wiring. Check for intermittent problem. See INACTIVE TROUBLE CODE CONDITION . Perform TEST VER-2A - ROAD TEST VERIFICATION .
  10. Using scan tester, stop all tests. Turn ignition off. Disconnect connector at idle air control motor. Idle air control motor is mounted on the throttle body and contains a 4-pin connector.
  11. Using ohmmeter, check resistance between ground and terminal No. 4 (Gray/Red wire) on connector for idle air control motor. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Gray/Red wire between PCM and idle air control motor. Perform TEST VER-2A - ROAD TEST VERIFICATION . The PCM is located between driver's side front fender and power distribution center, near battery.
  12. Using ohmmeter, check resistance between ground and terminal No. 3 (Yellow/Black wire) on connector for idle air control motor. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Yellow/Black wire between PCM and idle air control motor. Perform TEST VER-2A - ROAD TEST VERIFICATION . The PCM is located between driver's side front fender and power distribution center, near battery.
  13. Using ohmmeter, check resistance between ground and terminal No. 2 (Brown/White wire) on connector for idle air control motor connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Brown/White wire between PCM and idle air control motor. Perform TEST VER-2A - ROAD TEST VERIFICATION . The PCM is located between driver's side front fender and power distribution center, near battery.
  14. Using ohmmeter, check resistance between ground and terminal No. 1 (Violet/Black wire) on connector for idle air control motor. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/Black wire between PCM and idle air control motor. Perform TEST VER-2A - ROAD TEST VERIFICATION . The PCM is located between driver's side front fender and power distribution center, near battery.
  15. Reinstall connnector on idle air control motor. Start engine and allow engine to idle. With engine idling, disconnect connector at idle air control motor.
  16. Using voltmeter, check voltage at terminal No. 4 (Gray/Red wire) on connector for idle air control motor. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, perform TEST TC-25B - IDLE AIR CONTROL MOTOR CIRCUITS .
  17. Using voltmeter, check voltage at terminal No. 3 (Yellow/Black wire) on connector for idle air control motor. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, perform TEST TC-25C - IDLE AIR CONTROL MOTOR CIRCUITS .
  18. Using voltmeter, check voltage at terminal No. 2 (Brown/White wire) on connector for idle air control motor. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, perform TEST TC-25D - IDLE AIR CONTROL MOTOR CIRCUITS .
  19. Using voltmeter, check voltage at terminal No. 1 (Violet/Black wire) on connector for idle air control motor. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, perform TEST TC-25E - IDLE AIR CONTROL MOTOR CIRCUITS .
  20. Turn ignition off. Disconnect connectors from Powertrain Control Module (PCM). The PCM is located between driver's side front fender and power distribution center, near battery.
  21. Check connectors for pushed out, miswired or damaged terminals. If terminals are not pushed out, miswired or damaged, go to next step. If terminals are pushed out, miswired or damaged, repair connectors as necessary. Perform TEST VER-2A - ROAD TEST VERIFICATION .
  22. Using ohmmeter, check resistance between terminal No. 4 (Gray/Red wire) on connector for idle air control motor and each remaining terminal on the connector. This checks for a short between idle air control motor driver circuits.
  23. If resistance is 5 ohms or more on all idle air control motor driver circuits, go to next step. If resistance is less than 5 ohms on any idle air control motor driver circuit, repair driver circuits that are shorted together. Perform TEST VER-2A - ROAD TEST VERIFICATION .
  24. Using ohmmeter, check resistance between terminal No. 3 (Yellow/Black wire) and terminals No. 2 (Brown/White wire) and No. 1 (Violet/Black wire) on connector for idle air control motor. If resistance is 5 ohms or more on idle air control motor driver circuits, go to next step. If resistance is less than 5 ohms on any idle air control motor driver circuit, repair driver circuits that are shorted together. Perform TEST VER-2A - ROAD TEST VERIFICATION .
  25. Using ohmmeter, check resistance between terminals No. 2 (Brown/White wire) and No. 1 (Violet/Black wire) on connector for idle air control motor. If resistance is less than 5 ohms on idle air control motor driver circuit, repair idle air control motor driver circuits that are shorted together. Perform TEST VER-2A - ROAD TEST VERIFICATION . If resistance is 5 ohms or more on idle air control motor driver circuit, replace idle air control motor. Perform TEST VER-2A - ROAD TEST VERIFICATION .
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