You have a 1996 Ford Windstar which sensor would you need to change if your error for the check engine light reads bank 2 sensor 2?

Answer 1

The sensor in question is the downstream catalyst monitor (O2 sensor) located on the exhaust pipe that comes off of the front exhaust manifold. But we really need to establish something so that you do not replace parts unnecessarily. A fault code from a sensor, especially an O2 sensor NEVER automatically means the sensor is bad. It means the PCM (main car computer) sees a reading that it doesn't like from that sensor.

In the case of an O2 sensor code, it means that the O2 sensor is either too rich or too lean, or not responding fast enough to suit the PCM. It could be a bad O2 sensor, or what usually is the case, is that there is a problem that is forcing the O2 sensor to read out-of-normal range, something like a vacuum leak, engine misfire, or in the case of your catalyst code, a bad catalytic converter.

The funny thing is, that you may actually replace the catalyst monitor (Downstream O2 sensor), and erase the code, then drive it, and think that you've fixed it, but you haven't. That particular code is a low-priority code, so it takes several consecutive drive cycles with that same problem, to get it to turn the light back on.

Don't blame Ford, blame the EPA. They are the ones who decided that the system has to operate this way for all cars sold in the US.