Sebring 2006

Idle Air Control Valve

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Operation



The Powertrain Control Module (PCM) adjusts engine idle speed through the Idle Air Control (IAC) valve to compensate for engine load, coolant temperature, or barometric pressure changes. The throttle body has an air bypass passage that provides air for the engine during closed throttle idle. The IAC valve regulates air flow through the bypass passage.

The PCM controls engine idle speed by adjusting the position of the IAC valve. The adjustments are based on inputs the PCM receives. The inputs are from the Throttle Position Sensor (TPS), Crankshaft Position (CKP) sensor, coolant temperature sensor, Manifold Absolute Pressure (MAP) sensor, Vehicle Speed Sensor (VSS) and various switch operations (brake, park/neutral, Air Conditioning (A/C)).

When the engine RPM is above idle speed, the IAC is used for the following functions:



Off-idle dashpot
 
Deceleration air flow control
 
A/C compressor load control (also opens the passage slightly before the compressor is engaged so that the engine RPM does not dip down when the compressor engages)
 

The target idle is determined by the following inputs:



Gear position
 
Engine Coolant Temperature (ECT) sensor
 
Battery voltage
 
Ambient/Battery Temperature Sensor
 
VSS
 
TPS
 
MAP Sensor
 

Removal & Installation



2.4L Engines

WARNING
When servicing throttle body components, always reassemble components with new O-rings and seals where applicable. Never use lubricants on O-rings or seals; damage may result.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative cable from the battery.
  4.  
  5. Remove the electrical connector from the Idle Air Control (IAC) valve.
  6.  
  7. Remove IAC valve mounting screws.
  8.  
  9. Remove the IAC valve from the throttle body. Ensure the O-ring is removed with the valve.
  10.  

To install:


NOTE
When servicing throttle body components, always reassemble components with new O-rings and seals where applicable.



Click image to see an enlarged view

Fig. When servicing throttle body components, always reassemble components with new O-rings and seals where applicable

  1. The new IAC valve has a new O-ring installed on it.
  2.  
  3. Carefully place the IAC valve into the throttle body.
  4.  
  5. Install the mounting screw. Tighten screw to 44 inch lbs. (5 Nm) torque.
  6.  
  7. Connect the electrical connector to the IAC valve.
  8.  
  9. Connect the negative cable to battery.
  10.  

2.7L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Disconnect the Idle Air Control (IAC) valve electrical connector.
  6.  
  7. Remove the IAC valve mounting screw.
  8.  
  9. Remove the IAC valve.
  10.  

To install:

  1. Install the IAC valve to the throttle body.
  2.  
  3. Tighten the mounting screws to 44 inch lbs. (5 Nm) torque.
  4.  
  5. Attach the electrical connector to the IAC valve.
  6.  
  7. Connect the negative battery cable.
  8.  

Testing




NOTE
If the engine will not idle, maintain an engine speed between 800 and 1,500 RPM.

  1. Start the engine. Allow the engine to idle. With the DRBIII®, read the Idle Air Control (IAC) Current. Is the IAC Current above 999 mA-
    1. If yes, go to step 2.
    2.  
    3. If no, look for an intermittent condition symptom. Perform POWERTRAIN VERIFICATION TEST VER-5.
    4.  

  2.  
  3. Turn the ignition off. Disconnect the IAC Motor harness connector. With the DRBIII®, monitor the IAC Current. Turn the ignition ON. Does the DRBIII® display IAC Current at 0 mA-
    1. If yes, replace the IAC Motor. Perform POWERTRAIN VERIFICATION TEST VER-5.
    2.  
    3. If no, go to step 3.
    4.  

  4.  
  5. Turn the ignition OFF. Disconnect the IAC Motor harness connector. Turn the ignition ON.
    1. With the DRBIII®, actuate the ASD Relay.
    2.  
    3. Measure the voltage of the (K60) IAC Signal circuit in the IAC Motor harness connector. Is the voltage above 0.5 of a volt-

      If yes, repair the short to voltage in the (K60) IAC Signal circuit. Perform POWERTRAIN VERIFICATION TEST VER-5
       
      If no, go to step 4
       

    4.  

  6.  
  7. Turn the ignition OFF. Disconnect the IAC Motor harness connector. Turn the ignition ON.
    1. With the DRBIII®, actuate the ASD Relay.
    2.  
    3. Measure the voltage of the (K39) IAC Motor Driver circuit in the IAC Motor harness connector. Is the voltage above 0.5 of a volt-

      If yes, repair the short to voltage in the (K39) IAC Motor Control circuit. Perform POWERTRAIN VERIFICATION TEST VER-5.
       
      If no, got to step 5
       

    4.  

  8.  
  9. Turn the ignition OFF. Disconnect the IAC Motor harness connector.
    1. Disconnect the Powertrain Control Module (PCM) harness connector.
    2.  
    3. Measure the resistance across the IAC Motor harness connector. Is the resistance below 5.0 ohms-
      NOTE
      Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.



      If yes, repair the (K60) IAC Motor Signal circuit short to the (K39) IAC Motor Control circuit. Perform POWERTRAIN VERIFICATION TEST VER-5.
       
      If no, go to step 6
       

    4.  

  10.  
  11. If there are no possible causes remaining, replace and program the Powertrain Control Module (PCM). Perform POWERTRAIN VERIFICATION TEST VER-5.

    Click image to see an enlarged view

    Fig. Idle Air Control (IAC) valve connector end view

  12.  

 
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