P0161 Code Won't Go Away

[Boboddy]

Had a P0161 code pop up for my 01 Sahara. Replaced all the 02 sensors with NTK but it still wouldn’t go away. Went away on its own and came back.

Any ideas? The wiring on the 02 sensor itself is fine but the wiring of the harness for bank 2 sensor 2 is difficult to get at

 

[macleanflood]

How's it driving? Gas mileage? Speedo accurate?

Any way to monitor live ODB data? I like to watch the voltages and make sure they stay below .9v.

-Mac

 

[Boboddy]

How's it driving? Gas mileage? Speedo accurate?

Any way to monitor live ODB data? I like to watch the voltages and make sure they stay below .9v.

-Mac

It drives alright. Gas mileage has definitely decreased some though.

 

[Boboddy]

How's it driving? Gas mileage? Speedo accurate?

Any way to monitor live ODB data? I like to watch the voltages and make sure they stay below .9v.

-Mac

I think it is a couple mph off too and has the right speedo gear. Not sure if it’s related but it struggles on steep mountain roads. Won’t go over 2.5k-3k rpm.

Think that’s the pcm?

 

[macleanflood]

I'm thinking plugged cat or bad O2s. Or cracked exhaust manifold.

You can remove the O2s and create an exhaust leak (you'll get codes, ignore them) and see if it drives better.

That would point towards plugged cats.

You can monitor live ODB data and watch the voltages on the O2s. Crudely and simply put you don't want the voltage to go over .9v and you want it going up and down with throttle.

And you can visually check your exhaust with a can of seafoam. Start the engine, unplug the brake booster vacuum line from the master cylinder...dip in the bottle...rev it up some and pull it out of the bottle so it doesn't die. Should make a lot of smoke...so this is where a few friends or a couple of GoPros help you spot white smoke coming out of places it shouldn't be...like exhaust manifolds.

-Mac

 

[RMETeeJay]

When you replace them, the connector should make a solid click sound which tells you that it's fully connected. They are a pain to access, but luckily you only need to replace them every 75-100K.

You could also try a PCM reset. I do a reset when replacing any FI sensor to force it to relearn and it also helped a stubborn code to disappear.

https://wranglertjforum.com/threads/any-benefit-to-resetting-pcm.15762/post-254238

 

[AndyG]

Really take a close look where the wiring runs from that since you’re behind the block above the bell housing

I’m dealing with some things right now and from here on I will always really be paying attention to my harnesses better

 

[Offline246]

I'm thinking plugged cat or bad O2s. Or cracked exhaust manifold.

You can remove the O2s and create an exhaust leak (you'll get codes, ignore them) and see if it drives better.

That would point towards plugged cats.

You can monitor live ODB data and watch the voltages on the O2s. Crudely and simply put you don't want the voltage to go over .9v and you want it going up and down with throttle.

And you can visually check your exhaust with a can of seafoam. Start the engine, unplug the brake booster vacuum line from the master cylinder...dip in the bottle...rev it up some and pull it out of the bottle so it doesn't die. Should make a lot of smoke...so this is where a few friends or a couple of GoPros help you spot white smoke coming out of places it shouldn't be...like exhaust manifolds.

-Mac

agree with the plugged cat - that has been seen here on the forum many times.

 

[AndyG]

agree with the plugged cat - that has been seen here on the forum many times.

An infrared handheld thermometer will show a significant heat difference between the top and bottom of the cat if it is plugged

 

[jcw]

Looking for help with similar issue:
Replaced double precats with Eastern Standard/ Davico part (old ones were bad) and the 3rd cat I replaced with the same brand but for an XJ as it bolted right up to the first cat pipe.
As of now I don’t have anything bolted up behind the 3rd cat (sounds pretty awesome as a bonus)
I have changed all 4 O2 sensors with NGK

I’m getting P0161 (o2 2/2 heater performance) code

Could that have to do with there being nothing behind the 3rd cat and it’s staying too cold and throwing off the sensor?
Gas mileage sucks too