How many O2 sensors on an `01?

[bruker]

I have an `01 Windstar with 155,000 miles on it and I'm thinking about changing the O2 sensors on it. I haven't crawled around to see how many there are or where they are so I thought I'd check with you guys first.

[12Ounce]

There are 2 catalytic converters in the exhaust sytem. Each has a sensor "before", and a different sensor "after".... a total of 4 sensors.

But why would you want to change them? Unlike sensors of a decade or so back, they are not to be changed as a maintenance routine. If they begin to fail, the on-board diagnostic system (OBDII) will give you a code ("engine light") identifying a related failure.

[DRW1000]

Originally Posted by 12Ounce

There are 2 catalytic converters in the exhaust sytem. Each has a sensor "before", and a different sensor "after".... a total of 4 sensors.

But why would you want to change them? Unlike sensors of a decade or so back, they are not to be changed as a maintenance routine. If they begin to fail, the on-board diagnostic system (OBDII) will give you a code ("engine light") identifying a related failure.

Good point 12ounce. In fact if the CEL is off I would not worry about items such as these. Stick with the fluids (oil, tranny, steering, coolant...), filters (oil, air) and PCV valve, spark plugs and cables as maintenance items when their recommended interval comes up.

There are probably items I have missed but your PCM knows when your sensors are working or not and it isn't afraid to tell you.