Volvo: 1999 volvo v70 check engine light, oxygen sensors, 1999 volvo v70, oxygen sensors

Question
"check engine" light is on all the time, brought to AutoZone, their analyzer said code 1805, but that might not be right.  However, analyzer said three sensors or part of the system and item #1 was bad.  I assume its an oxygen sensor.  There's two on the exhaust, one just before catalytic and one in the catalytic.  I don't know what the third item could be.  Is there any way of finding which oxygen sensor is #1?  Also, the plugs for these two sensors look tough to get at, any helpful hints how to disconnect.  Also, Bosch units cost about $150, any truth to rumour that much cheaper Ford units will work.  Also, can an oxygen sensor be cleaned and re-used or tested to see if it is bad?

Thanks so much for your help.

Answer
Bob,
You need to find a shop that has the proper scanner to read codes and monitor the system so it can be determined what sensors are at fault. The 02 sensors have been a problem, so that indeed may be your problem. My past experience has shown that a replacement of 02 sensors with Volvo original are the best ones to use. They may also have a small wire harness that goes with the sensors.