Oxygen Sensor Hookups
 

I am in the process of re-installing my 3.6 motor in my 98 993 and just realized that I may not have properly marked the O2 leads when I disconnected them at the connectors on each of the fender wells in the engine bay. So, I have a couple of questions:

1, Can the O2 sensors be interchanged upstream and down stream of the cat? Or, are the connectors on the ends of the sensor leads different? If so, can someone provide information to make certain that I have the correct sensor installed in the correct bung on the cat.

2, And, if the answer to #1 is that the connectors are the same for both sensors…..then how do I identify which plug to install the upstream and down stream sensors? Obviously, I will have ECU issues if the O2 sensors are swapped in the wiring.

Normally, in similar situations, Porsche has been very good about color coding their connectors to prevent errors in installing them…..but, for the O2 sensors…….I don't see any difference between the sensor for the upstream or downstream side of the motor…..other than the fact that the sensors have different part numbers.

I just want to be sure.