ok so i have a 2002 jeep grand cherokee laredo 4.0 liter and i have 3 bad oxy sensors but i cant find a diagram or any kind of info on which one is which theres 2 right off the exhaust mani then theres a mini cat then two more after it.....i really would like to find out which ones are up and downstream and bank #'s so i can freaking get the right parts and put them in the right place....i cant believe theres nothing out there showing this info ive been looking for months its irritating can someone help me out please thanks in advanced
Bryan

 

Upstream is between engine and cat, downstream is after cat. Not sure why a 6 cyl would have 4 sensors.

 

Also, you may want to try posting in the Grand Cherokee section.

 

I have 4 sensors on mine. May be an 01 xj but same engine. Upstream front is the front downpipe before the cat, te rear upstream is the rear downpipe before the cat.

OP, what codes you getting. And, although I may be wrong, the main difference with the O2 is the length of the wiring. I ordered 2 of the same part number for my upper ones and never threw a code or lost gas mileage. One wire loom was really long though lol

 

 

How does he do it lol

 

Even though its an inline 6 they divided the cyl's into two banks. Bank 1 is the frt 3 cyls 1,2,3. Bank 2 is the rear 3 cyls, 4,5,6. Depending on your scanner/code reader and its definition the sensors might be referred to as Bank 1 sensor 1, Bank 1 sensor 2, Bank 2 sensor 1, Bank 2 sensor 2. Sensor 1 is before the cat, Sensor 2 is after the cat.

 

Well played

 

Here is a pic that should clear things up. The listed sensors are numbered "1/1" " 2/1" etc. The first number is the bank number for sensor. The second number is location on the bank, where #1 is upstream or before cat, #2 is downstream or after cat. Terminology might look a little different depending on what manual, or code reader you use but the bank designation number is always first, then the location number in exhaust.