B_Swapped93

I bought a tsx it's an 05 auto nothing too fancy, it's mint other then the fact that this p0139 comes on and off "slow o2 sensor #2". it has 90K miles extremely well taken care of, my friend said slow o2 usually means it's on it's way out?. I'm buying an OEM Honda one if so, i'd just like to know I have an emissions text very soon.

100% BONE stock

EnjoyTheRideDC2

iTrader: (1)

You should check with the previous owner if the o2 sensor was previously replaced. Dont be surprised if you remove it only to discover its an aftermarket replacement.

Usual culprits for this code are the rear o2 sensor, an exhaust leak, or the catalytic converter failing.

B_Swapped93

was from some guy in his 60's he just took it to a garage always sadly never kept the slips so I can't see the work order. It comes and goes I see no pattern, it went off today when I went to order my o2 from Honda which would rule out exhaust leak? as for the cat it looks new going to jack up the car and look tho tonight.

EnjoyTheRideDC2

iTrader: (1)

There is usually no pattern or drivability issues when the code is triggered. No specific driving action cause the CEL to go off. P0139 is an intermittent code, only going off when the response time between readings are delayed.

I'm not sure how an exhaust leak can be ruled out just since you haven't taken a look under the car yet. Typical diagnostics for this issue involve reading the a/f data being received by the rear o2 sensor. Chances are your rear o2 sensor is out, you've got an exhaust leak, or your catalytic converter needs to be replaced.

Something to consider: Instead of buying parts suggested by others without knowing for sure its the cause of the problem, you should get yourself a diagnostic reader to help troubleshoot future issues. I'm sure you can get your hands on a laptop to log and monitor all the data needed to diagnose engine issues.

For instance, you could replace your secondary o2 sensor and assume the problem is solved since the CEL hasn't illuminated like before...then a couple weeks later it comes back. Since it only goes off if the condition is detected after 2 consecutive drive cycles, you might not know if the problem still exists until weeks or months from now till the CEL comes on again.

B_Swapped93

No exhaust leaks all flanges prior to the cat are fine and the gaskets seem fine, the CAT looks new the o2 won't come out and I cat tell if it's oem or not.

tony_2018

I've read the sensor could be fouled out due to carb build up.

EnjoyTheRideDC2

iTrader: (1)

What are you using to remove the sensor?

No visual inspection alone is going to be able to determine the reason for your P0139. Since you already purchased the sensor, replace it and get your e-test taken. If the code reappears, talk to the dealer and see if they will repair the car under the emissions warranty. I believe the warranty period was extended from the original 8yr/100k mile but i'm not sure if the same was done in Canada.

B_Swapped93

That's what my friends keep saying.


I'd be just over when you convert the miles to km's I just used a mile reference for the heavy US presence here. i'm using one of these o2 sensor sockets but it's suck very well.

EnjoyTheRideDC2

iTrader: (1)

Since you're replacing it, try to spray PB blaster around the top and let it soak in there. Then take the car for a decent drive to warm up the catalytic converter. Get back, raise the car and make sure its firmly on stands. Use a breaker bar to break the sensor loose.

I assume you're attempting this job while laying on your back. You might not be giving yourself enough space to work. Try supporting the car higher so you can have more leverage. But definitely use a spray lubricant and heat up the sensor.

EnjoyTheRideDC2

iTrader: (1)

Worse comes to worse, clip off the wires and slip a 6 point socket on the head with a breaker bar.

B_Swapped93

Took the car for safety inspection today asked that they remove the o2, apparently after heating it to the point of it being red(oxy/acl torch) I still won't move. I assume just get another magna-flow cat for $80? anyone know the stock tsx exhaust size?

EnjoyTheRideDC2

iTrader: (1)

What kind of people do you take your cars to?

I understand o2 sensors can be stubborn to remove, but you dont hear people changing their cat due to a seized o2 sensor. In the end, the decision is yours. If you dont have the ability to remove the o2 sensor yourself and cant find a competant mechanic to do the job, then I guess grab a new catalytic converter.

You say to get "another" magnaflow cat... is that what you currently have in the car right now? If so, you might want to really inspect for leaks since the cat had been replaced. A simple gasket replacement might be all thats needed.

Main exhaust piping is 54mm in diameter.... 2.25" converters are the typical aftermarket size used for replacement on oem piping.

B_Swapped93

Small town garage that has always done good by me when I needed welding etc. There is a chance they lied an didn't even try i'm going to try what you suggested I have a deep 22mm in 1/2 and a new bigger jack so i'll give that a shot on the weekend. Yes it's a generic magna-flow "looks" fine

EnjoyTheRideDC2

iTrader: (1)

You can always remove the cat from the exhaust system and mount it on a vise, grab your 1/2'' breaker bar, 22mm socket, spray pb blaster on the sensor junction, and break that thing loose. That way you wont be tugging on the exhaust mounts and you'll be in a better position than laying on your back and trying to loosen it.

Although, I would consider changing your exhaust gaskets where they meet @ the catalytic converter first and see if the problem still persists. Would be better to analyze freeze frame data when the CEL is triggered...but thats up to you if you want to invest less than 50 bucks for that ability.

EnjoyTheRideDC2

iTrader: (1)

Another thought : Since you have an aftermarket catalytic converter, assuming its a universal one due to the price point you mentioned earlier, the o2 sensor might not be mounted in the exact place the original one was, therefore causing the delay in response from the o2 sensor.

B_Swapped93

The light is always on now and there 2 new codes no more "slow o2". Snipped the wires and put a deep 22 one there's virtually no leverage under the car I bought 2 mew jacks even still noting. So it's going to Honda this week..

EnjoyTheRideDC2

iTrader: (1)

Why dont you remove the exhaust section from the car to work on the sensor? Or drop the catalytic converter and mount it on a vise so you can get leverage in whatever way best suits you?

That o2 sensor will be impossible to break loose without using either a torch or penetrating fluid to soak the threads.

B_Swapped93

It was the o2 sensor it's been good for 2 weeks now, in case anyone comes across this thread.