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Oxygen sensor locations on a 99 cougar V6?

12K views 9 replies 5 participants last post by  fastcatcougar03 
#1 ·
Oqygen sensor locations on a 99 cougar V6?

I know there are two up front right? looking from underneath the car there is one lower and one higher on the precat. There is another behind the cat converter too, right? that would make a total of three? I have a CEL light on and am going to replace one. I checked the two up front and the bottom one looks all black and may be the problem one. Is this usually the one that causes the cell to come on?
Thanks for the help,
Ron
 
#2 ·
Big Ron... what's up, buddy. Welcome to NECO.

You have 4 Oxygen sensors on your vehicle. To be absolutely correct, you have two Oxygen Sensors, and two Catalyst Efficiency monitors. The two O2's are located in the exhaust manifolds right at the top of the joined section. They call these the upper O2's. For the lower ones, there is one in the front exhaust manifold after the pre-cat section (that's the large section all the ports combine into), and one in the stock Y-pipe just after the rear bank exhaust manifold / exhaust header. What's your code? It will identify which O2 is bad, if I recall correctly.

Massiv.
 
#5 ·
Originally posted by: nullxposur
I have a similar problem too. I have a code P0420: Catalytic Efficiency below threshhold. I know it's the Bank 1, but I'm not really sure which one that is where it's located. Any help???
That would be the "rear" bank, which means the sensor inquestion is the one in the Y-pipe. Lower rear sensor.
 
#6 ·
I knew it was the rear one. I was just wondering if it was the one on top, between the rear of the engine and the firewall (the one that's really hard to get to) or the one on the bottom rear of the engine. I had just heard somewhere else that it was the first one (the rear, top one) but i wasn't sure.

???
 
#7 ·
Originally posted by: nullxposur
I knew it was the rear one. I was just wondering if it was the one on top, between the rear of the engine and the firewall (the one that's really hard to get to) or the one on the bottom rear of the engine. I had just heard somewhere else that it was the first one (the rear, top one) but i wasn't sure. ???
Originally posted by: Massiv
Big Ron... what's up, buddy. Welcome to NECO.

You have 4 Oxygen sensors on your vehicle. To be absolutely correct, you have two Oxygen Sensors, and two Catalyst Efficiency monitors. The two O2's are located in the exhaust manifolds right at the top of the joined section. They call these the upper O2's. For the lower ones, there is one in the front exhaust manifold after the pre-cat section (that's the large section all the ports combine into), and one in the stock Y-pipe just after the rear bank exhaust manifold / exhaust header. What's your code? It will identify which O2 is bad, if I recall correctly.
Based on the fact that your code is saying you have a catalyst efficiency issue, it would have to be the ones after the precat, wouldn't it? The ones called "Catalyst Efficiency" monitors?
;)

Looking at someone else's thread, those are like $350 for a new one, if it is actually the catalyst material and not the C.E. monitor! I might have an extra one which is BRAND NEW...

Massiv.
 
#9 ·
My question isn't totally off topic, but is the oxygen sensor heated? page four of the instruction booklet from autometer; http://hp.autometer.com/instructions/007175_instruction.pdf . i am installing the air/fuel ratio gauge, from autometer... (C2) and don't know which sensor we have in the 2000 mercury cougar.
 
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