Accord OBD code reader result - what does it mean?

[sr17]

Check engine light has appeared and disappeared a few times lately in my 2005 Honda Accord. The also shudders a bit under load at times.

Stopped by O'Reilly Auto Parts and borrowed a code reader.

The code that came up reads: PO139 02 Circuit Slow.

I have no idea what this actually means. Hoping the BITOG community can enlighten me?

 

[Colt45ws]

Bad O2 sensor would be my first guess.

 

[R2d2]

secondary o2 sensor is sluggish, needs to be replaced you can probably do it yourself.

 

[JHZR2]

+1. O2 sensors get lazy before they fail. Swap both and see what happens.

 

[4D-56]

google it!

 

[sr17]

Thanks guys.

What are the typical symptoms for o2 sensor failure?

Check engine light has come on a few times, but it will disappear again for a long time - a couple of months. Whether it is pure coincidence, I don't know, but it seems to light up when gas tank is low, and after filling the tank, it would disappear again.

The car also shudders a bit under load at freeway speeds - not when going slower. Could this be related to the same, or is it likely a separate issue that does not cause any codes?

 

[hsd]

P0139 is the secondary (rear) O2 sensor has slow response. It measns either your secondary O2 sensor is going bad or your converter is about shot. Neither one will cause drivability problems, but you might have a problem passing emisions if the local authority has emision testing. Use a genuine Honda O2 sensor if you change it.

 

[sr17]

So would you say with certainty that the shudder that I experience under load at hwy speeds is not a related issue?

 

[sr17]

Would a spark plug / wire, or coil problem cause a different code, or none at all?

I am trying to determine what causes the shudder.

 

[Vikas]

Most likely unrelated. Please check your ignition system e.g. spark plugs, wires/coil etc first. The secondary sensor is only for the emission sticker. It can not cause drive-ability problems.

 

[Tegger]

Originally Posted By: sr17
So would you say with certainty that the shudder that I experience under load at hwy speeds is not a related issue?

Not related. The shudder is either worn inner CV joints, or a worn bearing in the transmission.

 

[vssjim]

Some times honda's do get trans shutter, honda tells you to first change the trans oil three or four times and see if it goes away. I mean like change it drive it five miles and change it again 3 or 4 times. We do this on the lifts at work. Had a Civic afew weeks ago and fixed his shutter problem. If not you have a problem somewhere else. As far as the O2 sensor slow response code for the down stream O2 just replace it, they are fairly cheap and easy to change.

 

[sr17]

Thanks guys, feedback much appreciated!

As far as it possibly being transmission related - my Accord has a manual transmission - does that change anything?

IF it was plugs, wires or coil - would there be any codes stored in the brain for that?

 

[Vikas]

Let us take this from beginning.

Given this is a 2005 model, it most likely has coil on plugs. They are known to go bad but when they do, you will get random misfire code P0300. Did you ever see the check engine light flashing when the shudder happens? If so, it is definitely misfiring under load. When you hook up the scanner, make sure you get all the codes instead of the first one only.

If you do not know the history of this vehicle, put the NGK/Denso Iridium or Platinum OEM plugs first before chasing any other issues. Also make sure the battery is reasonably new and there is no visible corrosion the posts and cable.

It is highly unlikely that clutch would be shuddering. How does clutch feel? Where in the pedal travel it engages and disengages? If if feels fine, it would not be cause of your problem.

Go for simple things first.

- Vikas

 

[sr17]

Thanks Vikas.

I have owned this vehicle since new. The car now has 157K Miles on it and reliability has been nothing short of remarkable - at least compared to anything I have owned in the past.

New Denso irridium plugs were installed at 129K Miles. Battery was replaced 9 months ago.

Check engine light never flashed in connection with the shudder.

Clutch feel appears normal to me, it does not appear to slip and there is no smell.

Transmission has Red Line MTL in it and shifts are very smooth

Car has developed a bit of the dreaded piston slap that seems to haunt many higher mileage Honda's, but it pulls as strong as it did when it was new.

Tires have been rotated and balanced and that did not change anything.

 

[Vikas]

I also looked at your picture again and you only have one code as indicated by 01/01.

Does the car shudder all the time? Or can you get it shudder it in your garage? For example, you could put as much load on the engine as possible i.e. turn on every accessory and see if you can reproduce the shudder. If you can, then use the cylinder balance test to sequential disable one cylinder at a time to find the one which is not contributing.

If you have a weak injector, putting some strong fuel system cleaner will only help. You did not mention trying that, so I do not know if you have already done that.

I am otherwise out of ideas. If you do find your problem, please update this topic. I suspect unless you come across a *great mechanic*, you might end up waiting until the problem gets progressively worse before nailing it down.

- Vikas

 

[sr17]

Thanks again Vikas - your postings have helped me better understand the variety of things that could be causing this issue.

The shudder is only evident under load, mainly in 5 th gear, but can be felt a bit in 4 th too sometimes. Only noticed at hwy speeds.

I have a bottle of SI-1 Complete Fuel System Cleaner in the tank right now - so far no change - about 150 Miles.

I hardly ever buy "no name" gasoline - 80% of the time it is Chevron, so I have my doubts that it is contamination.

The shudder has been there for the last 10K Miles or so, and it does not seem to be getting worse - so far.

 

[Vikas]

If you are willing to throw parts at it, buy a singe new coil (OEM or better quality) and replace one at a time and drive the car i.e. put the new on the cyl #1 and if that does not fix it, use the removed coil to swap the one from cyl #2 etc. The coil should cost you between $50-$100; a single trip to dealer would costs you lot more!

Personally, I do not think Honda coils go bad slowly i.e. when they die, they die pretty catastrophically giving you constant misfire and codes.

I am surprised that you are not getting any misfire or EGR code but are getting secondary O2 code. This means your OBD-II is functioning and at least ECM does not believe you have either of those issues.

You could start tracking the fuel system but that gets difficult. I do not have much experience in measure fuel pressure etc but from what I have read, it is not too difficult to hook up a gauge to the fuel rail and monitor the pressure. If the pressure is on the low side and if you see it dropping during the shudder, it could be the fuel pump. I feel that lack of fuel under load would make the car feel like it is "choking" rather than "shuddering"; more experienced members might refute that claim though.

- Vikas

 

[joel95ex]

clean the EGR system. many have reported a shutter with clogged egr ports. also, it will only help your overall emissions system. I have done mine 3 times. I'm at 408K miles now.