LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Jeep >> 2000 >> Wrangler SE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Idle Control Systems >> Checking Idle Air Control Motor
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Checking Idle Air Control Motor

NOTE: For circuit identification and wiring diagram, see WIRING DIAGRAMS article. After each repair procedure has been completed, reconnect all components. Perform TEST VER-2  under VERIFICATION TESTS to ensure system is functioning properly.
  1. Start engine an allow it to reach normal operating temperature. Using scan tool, actuate Idle Air Control (IAC) motor to 1400 RPM. If engine speed is not 1300-1500 RPM, go to next step. If engine speed is 1300-1500 RPM, stop actuation. IAC motor is operating properly this time. Test is complete.
  2. Start engine and allow it to idle. Check engine, brake booster and vacuum hoses for leaks. Repair vacuum leaks as necessary. If no vacuum leaks exist, go to next step.
  3. Turn ignition off. Disconnect IAC motor connector. IAC motor is located on throttle body. Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector and terminals as necessary. If connector and terminals are okay, go to next step.
  4. Ensure ignition is off. Disconnect PCM connectors. See POWERTRAIN CONTROL MODULE LOCATION  table. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Gray/Red wire (2.5L and 4.0L) or Gray/Black wire (4.7L) at IAC 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 Gray/Red wire or Gray/Black wire between IAC motor and PCM.
    POWERTRAIN CONTROL MODULE LOCATION

    Application Location
    Cherokee In Engine Compartment On Left Front Fender, Near Radiator Support
    Grand Cherokee & Wrangler On Firewall In Right Rear Corner Of Engine Compartment
    5. NOTE: Voltage may switch or remain constant in this step.
  5. Ensure ignition is off and IAC motor is still disconnected. Reconnect PCM connectors. Turn ignition on, with engine off. Using scan tool in actuator tests mode, actuate IAC stepper motor. Measure voltage between ground and Gray/Red wire (2.5L and 4.0L) or Gray/Black wire (4.7L) at IAC motor connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not 5 volts or more at any time, perform DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS test under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
  6. Ensure ignition is off. Disconnect PCM connectors. Measure resistance between ground and Yellow/Black wire at IAC 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 Yellow/Black wire between IAC motor and PCM.
    7. NOTE: Voltage may switch or remain constant in this step.
  7. Ensure ignition is off and IAC motor is still disconnected. Reconnect PCM connectors. Turn ignition on, with engine off. Using scan tool in actuator tests mode, actuate IAC stepper motor. Measure voltage between ground and Yellow/Black wire at IAC motor connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not 5 volts or more at any time, perform DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS test under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
  8. Ensure ignition is off. Disconnect PCM connectors. Measure resistance between ground and Brown/White wire at IAC 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 IAC motor and PCM.
    9. NOTE: Voltage may switch or remain constant in this step.
  9. Ensure ignition is off and IAC motor is still disconnected. Reconnect PCM connectors. Turn ignition on, with engine off. Using scan tool in actuator tests mode, actuate IAC stepper motor. Measure voltage between ground and Brown/White wire at IAC motor connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not 5 volts or more at any time, perform DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS test under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
  10. Ensure ignition is off. Disconnect PCM connectors. Measure resistance between ground and Violet/Black wire at IAC 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 Violet/Black wire between IAC motor and PCM.
    11. NOTE: Voltage may switch or remain constant in this step.
  11. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on, with engine off. Using scan tool in actuator tests mode, actuate IAC stepper motor. Measure voltage between ground and Violet/Black wire at IAC motor connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not 5 volts or more at any time, perform DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS test under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
  12. Turn ignition off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. On 2.5L and 4.0L Cherokee and Wrangler, measure resistance between Gray/Red wire and Yellow/Black, Brown/White and Violet/Black wires at IAC motor connector. On 4.7L, measure resistance between Gray/Black wire and Yellow/Black, Brown/White and Violet/Black wires at IAC motor connector. On all models, if all resistance readings are 5 ohms or more, go to next step. If any resistance reading is less than 5 ohms, wiring is shorted together. Repair wiring as necessary.
  13. Measure resistance between Yellow/Black wire and Brown/White and Violet/Black wires at IAC motor connector. If all resistance readings are 5 ohms or more, go to next step. If any resistance reading is less than 5 ohms, wiring is shorted together. Repair wiring as necessary.
  14. Measure resistance between Brown/White wire and Violet/Black wire at IAC motor connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Brown/White wire is shorted to Violet/Black wire. Repair wiring as necessary.
  15. At this time, IAC motor is assumed to be defective. Replace IAC motor.
scientia non olet · About LEMON Manuals