Q: Idle air valve calibration/adjustment

asked by on October 27, 2016

Hi! Recently I managed to clean the lean error code by replacing the intake gasket(upper) and the throttle body gasket as well. No more code to address now, except that I think I need to calibrate my idle air valve duty or counts. Perhaps the previous owner might had messed up with the bypass screw on top of the throttle body due to the lean condition perhaps. Is there a way I can adjust it again without using a bidirectional scan tool? At least to hit 50% or so duty cycle. Our Mitsu dealer MUT tool is not working. Thanks
My car has an automatic transmission.

Hi there. It is suggested to have a bidirectional scan tool but it is not required. Verify the idle speed is within 650-750 rpm. You want to be at 700 rpm ideally. Connect data link connector terminals TEN & GND by using a jumper wire. Adjust the idle speed by turning the air adjusting screw until smooth running anywhere between 500-800 rpm. Disconnect the jumper wire and recheck the RPM’s on the meter. If you need further help adjusting your idle, a qualified professional from YourMechanic can come to your car’s location to pinpoint the proper repairs.

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