Originally Posted by KENMO
Asking for my Dad, so please be kind...
My Dad has a 2002 Ford Windstar with a 3.8L V6. Can anyone kindly let me know where the OSS sensor is located? He's getting a P0720 OBD2 code and it is indicating the OSS sensor needs replacing. He has previously replaced the TSS sensor and that was too easy to find...
the OSS is found on the main part of the case down about 1/2 way. its directly under the exhaust manifold on the firewall side.
even though i have seen those sensors fail but, with the explanation that the ISS (turbine sensor) has already been replaced already could lead to something else wrong. it could be a ground or pcm issue, a problem with the wiring harness or, it could be internal.
the best thing to do is remove the sensor and check with a DVOM, or take the vehicle to a transmission shop and have them drive it with a scan tool hooked up in data stream mode to verify OSS operation (or the lack there of).