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Test KE: Idle Air Control Valve: Testing

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NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P0505    KE2  
P0506    KE2  KE2
P0507    KE2  KE2
P0511  KE2  KE2  
P1504  KE2  KE2  KE2
P1506      KE20
P1507    KE2  KE2
    NOTE: Step  1) is performed when directed here from SYMPTOMS in TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.

  1. 1) Idle Concerns Or Engine Stalls: Perform KOER On-Demand Self-Test & Output Continuous Memory DTCs
    Symptom diagnosis indicated that there was no idle change when IAC valve was disconnected. Perform KOER ON-DEMAND SELF-TEST . Retrieve and record all Continuous Memory DTCs. If unable to complete KOER self-test, go to next step. If KOER self-test is complete and DTC P0505, P1504 or P1507 is present, go to next step. If DTC P0505, P1504 or P1507 are not present, IAC system is okay and testing is complete. If symptom still exists, return to symptom that directed you here under SYMPTOMS under TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.
    2. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: If EGR DTC P0402 was output during KOER self-test, service DTC P0402 prior to continuing with this test.

  2. 2) For KOER Only DTC P0505, For KOER & Continuous Memory DTCs P0506, P0507 & P1507, For KOEO, KOER & Continuous Memory DTC P1504: Or Starts Only At Part Throttle; Check VPWR Voltage To IAC Valve
    KOER DTC P0505 is set when PCM attempts to control engine idle speed and desired RPM could not be reached or controlled during self-test. KOEO, KOER and Continuous Memory DTC P1504 is set when PCM detects an electrical load failure on IAC output circuit. KOER and Continuous Memory DTC P1507 is set when PCM detects engine idle speed is less than desired RPM. Possible causes are:
    • IAC Circuit Open, Or Shorted To GND Or VPWR
    • VPWR Circuit To IAC Valve Open
    • Air Inlet Plugged
    • Faulty IAC Valve
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect IAC valve connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and VPWR circuit at IAC valve harness connector. See Figure. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.

  3. 3) Check IAC Valve Resistance

    Turn ignition switch to OFF position. Using a DVOM, measure resistance between both IAC valve terminals. If resistance is 6-13 ohms, go to next step. If resistance is not 6-13 ohms, replace IAC valve.

  4. 4) Check IAC Valve For Internal Short To IAC Case

    Ensure ignition switch is turned to OFF position. Using a DVOM, measure resistance between IAC valve case and each IAC valve terminal. If both resistance measurements are more than 10 k/ohms, go to step  7) (DTC P1504), or go to next step (all others). If either resistance measurement is 10 k/ohms or less, replace IAC valve.

  5. 5) Check Air Inlet For Plugging

    Turn ignition switch to OFF position. Remove air filter. Inspect air filter, Mass Airflow (MAF) sensor and air inlet system for debris, blockage, excessive dirt or contamination. Repair as necessary. If air inlet system is okay, reinstall inlet air system and go to next step.

  6. 6) Check For Inlet Air Leaks

    Start engine and allow to idle. Listen for vacuum leaks. Inspect air inlet system from MAF sensor to intake manifold for any of the following possible faults:
    • Cracked Or Punctured Air Inlet Tube
    • Loose Inlet Air Tube, IAC Tubes Or Air Cleaner Housing
    • Loose Or Damaged Throttle Body
    • Contaminated Or Damaged IAC Valve, Or Gasket
    • Faulty EGR Valve Or Gasket
    • Damaged Vacuum Supply Connector Or Hose(s)
    • Faulty PCV Valve, Connector Or Hose

    Check entire intake air system for vacuum leaks. Repair as necessary. If no vacuum leaks are found, go to next step.

  7. 7) Check IAC Circuit For Open In Harness

    Turn ignition switch to OFF position. Disconnect IAC valve connector. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of IAC circuit between PCM harness connector and IAC valve harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is 5 ohms or more, repair open in IAC circuit. If resistance is less than 5 ohms, go to next step.

  8. 8) Check IAC Circuit For Short To PWR In Harness

    Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and IAC circuit at PCM harness connector. If voltage is one volt or more, repair short to PWR in IAC circuit. If voltage is less than one volt, go to next step.

  9. 9) Check IAC Circuit For Short To Ground In Harness

    Turn ignition switch to OFF position. Disconnect scan tool from DLC. Using a DVOM, measure resistance between IAC and PWR GND circuits at PCM harness connector. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION table. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, replace PCM (DTC P0511, P1504), or go to next step (all others). If resistance is 10 k/ohms or less, repair short to ground in IAC circuit.

  10. 10) Check IAC Signal From PCM

    Reconnect PCM and IAC valve harness connectors. Start engine and allow to idle. If engine stalls, place a shim under hard stop screw to maintain idle conditions. Using scan tool, access IAC and RPM PIDs from PID/DATA MONITOR & RECORD menu. Ensure engine is at normal operating temperature. With all accessories off and throttle closed, IAC duty cycle should be about 22-45 percent. Observe IAC PID value and slowly increase engine speed to 3000 RPM, then allow to return to closed throttle position (if closed throttle RPM is significantly higher than normal, ignore this part of the procedure). IAC duty cycle should increase as engine speed increases. If IAC PID value is not within specification at closed throttle or duty cycle does not respond to RPM change, replace IAC valve. If IAC PID value is within specification at closed throttle and duty cycle does respond to RPM change, go to step  30) (DTC P1504 or P1507), or check throttle body for damage (all others). Repair as necessary. If throttle body is okay, replace IAC valve and perform PCM RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 10) to step 20). No test procedures have been omitted.
    11. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  11. 20) For Continuous Memory Only DTC P1506: Check For Vacuum Leaks
    DTC P1506 is set when PCM detects engine idle speed is more than desired RPM. Possible causes are:
    • IAC Circuit Short To GND
    • Damaged IAC Valve
    • IAC Valve Stuck Open
    • Vacuum Leaks
    • Faulty EVAP System
    • Damaged Powertrain Control Module (PCM)

    Start engine and allow to idle. Listen for vacuum leaks. Inspect air inlet system from Mass Airflow (MAF) sensor to intake manifold for any of the following possible faults:

    • Cracked Or Punctured Air Inlet Tube
    • Loose Inlet Air Tube, IAC Tubes Or Air Cleaner Housing
    • Loose Or Damaged Throttle Body
    • Contaminated Or Damaged IAC Valve, Or Gasket
    • Faulty EGR Valve Or Gasket
    • Damaged Vacuum Supply Connector Or Hose(s)
    • Faulty PCV Valve, Connector Or Hose

    Check entire intake air system for vacuum leaks. Repair as necessary. If no vacuum leaks are found, go to next step.

    12. NOTE: EVAP canister is also referred to as carbon canister.
    Fig 1: Identifying EVAP Canister Purge Valve & Hose Ports
    G00088385Courtesy of FORD MOTOR CO.
    Fig 2: Identifying Vapor Management Valve & Hose Ports
    G96C01029Courtesy of FORD MOTOR CO.

  12. 21) Check EVAP System For Stuck Open Valve
    Turn ignition switch to OFF position. Disconnect hoses from EVAP canister purge valve or Vapor Management Valve (VMV). Connect a vacuum pump to "Fuel Vapor To EVAP Canister" port on carbon canister and apply 16 in. Hg to port. See Fig 1 or Fig 2 . If vacuum bleeds off within 20 seconds, replace EVAP canister purge valve or VMV. If vacuum holds, reconnect hoses and go to next step.

  13. 22) Check IAC Valve For Proper Function

    Start engine and allow to idle. Ensure transmission is in Park or Neutral and engine has reached normal operating temperature. Disconnect IAC valve harness connector. If engine speed drops or engine stalls, go to next step. If engine speed does not drop or engine does not stall, check throttle body for damage. Repair or replace as necessary. If throttle body is okay, replace IAC valve and perform PCM RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM.

  14. 23) Check IAC Circuit For Short To GND In Harness

    Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between negative battery terminal and IAC circuit at PCM harness connector. See PCM CONNECTOR IDENTIFICATION and Figure. If resistance is more than 10 k/ohms, replace PCM (for high idle speed symptom), or reconnect all connectors and components and go to step  30) (all others). If resistance is 10 k/ohms or less, repair short to GND in IAC circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 23) to step 30). No test procedures have been omitted.

  15. 30) Check IAC System For Intermittent Open Or Short

    Connect scan tool to Data Link Connector (DLC). Start engine and allow to idle. Ensure all accessories are off and engine is warmed to normal operating temperature. Using scan tool, access IAC and RPM PIDs from PID/DATA MONITOR & RECORD menu. IAC duty cycle should be 20-45 percent. Observe IAC and RPM PIDs for indication of fault while performing the following:
    • Shake, wiggle and bend wiring harness starting at IAC valve and work toward PCM.
    • Lightly tap on IAC valve and wiggle connector to simulate road shock.

    Fault will be indicated by sudden change in IAC or RPM PID value. If any faults are found, isolate fault and repair as necessary. If no faults are found and an idle quality, starting or stalling symptom is currently present, replace IAC valve. If no faults are found, and idle is okay and a starting or stalling symptom is not currently present, check for intermittent faults. Go to TEST Z, step  1).

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