P0161 and other error codes

MuayThaiJeepGuy

MuayThaiJeepGuy

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Joined
Mar 19, 2022
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12
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New Jersey
Hey guys this is the third time this code has popped up now on my jeep in the past few months. Past two times took it to the shop and had it "fixed" but now I am suspicious as to why this same code keeps popping up. The reader is throwing P0161, O2 Sensor Bank 2, Sensor 2 and also telling me to Repair the Cylinder Head Ground wire. We have replaced all the O2 sensors and this particular sensor twice. The jeep seems to run fine even with this thrown code. Not sure what to make of this any insight is appreciated.
 
Do an inspection of the factory harness feeding the O2 sensors and the connector.
I would recommend taking a look at the three 32 pin harness connectors at the ECU for oxidation or loose connections.
Could hurt to also look at the communications harness from the ECU that is routed between the valve cover and firewall. The split wire loom harness is routed around a threaded head stud in the right rear corner that is known to rub thru the split wire loom and harness wire insulation.
Any one of these could cause a problem similar to what you are experiencing.
 
Right after buying my current TJ I was getting intermittent O2 sensor codes and it would idle roughly during those times. The previous owner had already replaced the O2 sensors so I just lived with it for several months until the root cause reared its ugly head. It turned out to be a bad pre-catalytic converter that let go on the highway and spilled its innards out into the exhaust plugging up the main catalytic converter which dropped my top speed to about 5 mph. Replacing all three cats and reusing the existing O2 sensors took care of it, it's been fine for 10+ years.
 
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Jerry is giving sound advice- You can actually pull the oxygen sensors and get a pretty good idea of the condition or even the existence of the catalytic converter media with a mirror or small scope, - I had one that the media was totally gone and another dropped 3/8” or so, separated from the pipe-

I know it is not fun to spend money on something like that but you might be surprised at how much performance you get back
 
CharlesHS said:
Do an inspection of the factory harness feeding the O2 sensors and the connector.
I would recommend taking a look at the three 32 pin harness connectors at the ECU for oxidation or loose connections.
Could hurt to also look at the communications harness from the ECU that is routed between the valve cover and firewall. The split wire loom harness is routed around a threaded head stud in the right rear corner that is known to rub thru the split wire loom and harness wire insulation.
Any one of these could cause a problem similar to what you are experiencing.
Click to expand...
Will do. Interestingly enough the shop I took it to said they looked at everything and could find anything like you're saying which makes me wonder what they even did the past two times?
Jerry Bransford said:
Right after buying my current TJ I was getting intermittent O2 sensor codes and it would idle roughly during those times. The previous owner had already replaced the O2 sensors so I just lived with it for several months until the root cause reared its ugly head. It turned out to be a bad pre-catalytic converter that let go on the highway and spilled its innards out into the exhaust plugging up the main catalytic converter which dropped my top speed to about 5 mph. Replacing all three cats and reusing the existing O2 sensors took care of it, it's been fine for 10+ years.
Click to expand...
Is there any way to test for something like that? Mine doesn't idle rough at all even with this thrown code.
 
AndyG said:
Jerry is giving sound advice- You can actually pull the oxygen sensors and get a pretty good idea of the condition or even the existence of the catalytic converter media with a mirror or small scope, - I had one that the media was totally gone and another dropped 3/8” or so, separated from the pipe-

I know it is not fun to spend money on something like that but you might be surprised at how much performance you get back
Click to expand...

I like keeping my stuff running well so I have no problem with this. Replacing what you guys said is probably my next move.
 
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You can get a scanner for about $159 at Harbor freight that will read live data and it will tell you your oxygen sensor voltage and also if you study fuel trim a little bit it will give you some idea if you’re getting some catalytic converter inefficiency - That and an infrared thermometer on the couch top and bottom will call give you an indication if there is a change in temperature via the cats

Don’t be intimidated it’s pretty simple and you can find a free good bit of information online on how to use the infrared
 
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