Toyota Celica, Corolla, ECHO & MR2 1999-05

Air Conditioning Idle Speed Compensator

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Operation



An A/C idle-up valve is used on these engines to raise the engine idle when the A/C is turned on.



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Fig. A/C idle-up system flow and wiring schematic-5S-FE engine



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Fig. A/C idle-up system flow and wiring schematic-7A-FE engine

Removal & Installation



Replacing the various vacuum switches simply requires unplugging the vacuum and/or electrical connections, then unbolting the switch. Inspect the vacuum hose over its entire length for any signs of cracking or splitting. The slightest leak can cause improper operation.



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Fig. A/C idle-up valve mounting



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Fig. A/C idle-up valve mounting-7A-FE engine

Testing



The A/C Idle-Up valve can be tested with the valve on or off the engine.

  1. Make sure all accessories are off.
  2.  



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Fig. The A/C Idle-Up valve retaining bolt (1), wiring connector (2) and air hose (3)

  1. Disconnect the idle-up valve wiring.
  2.  
  3. Label and remove the two hoses attached to the valve.
  4.  
  5. Remove the bolts and the valve.
  6.  
  7. Check the valve for and open circuit. Test the A/C idle-up valve using an ohmmeter, check that there is continuity between terminals. Resistance should be around 30-33 ohms at 68°F (20°C).
  8.  



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Fig. Testing for continuity on the A/C idle-up valve

  1. If it is not as specified, replace the VSV.
  2.  
  3. Check the valve for ground, with an ohmmeter, make sure there is not continuity between each terminal and the body.
  4.  



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Fig. Place the negative connector on the body and the positive on the terminal to test for ground



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Fig. The same test can be done with the valve on the vehicle

  1. If there is, replace the VSV.
  2.  
  3. Check the valve operation.
  4.  
  5. Check that air does not blow from pipe E to F .
  6.  



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Fig. Blow air into pipe E and check that it flows into pipe F of the VSV

  1. Apply positive battery voltage across the terminals. Check that air flows from pipe E to F .
  2.  
  3. If operation is not as specified, replace the VSV.
  4.  

 
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