Contour Enthusiasts Group Archives Forums General Troubleshooting Air Bypass Valve?

I searched 1st...

Can anyone tell me where the Air Bypass Valve is and what it does for your car. In this case a'98 CSVT.

Thanx much...


Reason asking is, after much effort (replacing the upstream biatch o2 sensor) and cleaning the MAF, the CEL that I have had would not go away. Getting both banks lean on the ODB II.

Considering my inspection sticker expired in April, and came up "untestable" when I tried to get it inspected after I changed the o2 sensor, I threw in the towel and took the car to an SVT dealership this am.

Verdict is a new MAF, new Air Bypass Valve, reprogram PCM.

Never heard of the Air Bypass Valve before...

Thanx for the info though!

I would imagine the "bypass" valve is the IAC. Just my opinion though, don't take it as truth.

no, the bypass valve is not the IAC. All I can find in the Haynes manual is....
The base idle speed is set in production by means of an air bypass screw (located in the front right hand corner of the TB)which controls the amount of air that is allowed to pass through a bypass stage, past the throttle valve when it is fully closed in idle position; the screw is then sealed with a white tamperproof plug. In service, the idle is controlled by the PCM.....the plug should not be altered, if it is altered it should be replaced with a blue tamperproof plug and let run for 5 minutes to let the PCM relearn the idle values.
Hope this helps a little.