First things first -- a big THANK YOU to this community! I have been lurking here for well over a year and this site was instrumental in finally deciding on + selecting a 3rd gen TL. Easter will mark my one-year anniversary as the proud owner of an '05 WDP 6MT! I have personally put over 21,000 miles on it in that time (including 900 highway miles driving it back to FL when I bought it -- what a way to get to know this car!) and am still thrilled + enamored with the TL!

Cliff's Notes: p0153 + p2a03 both point at the same o2 sensor, no obvious visual issues with connectors / wiring -- 1). Could this be the cause of random p0300-306 CEL, with replacement resolving the issue? 2). Can I replace this with Denso 234-5010? and 3). What else could it be? -- I'd like to resolve this ASAP and am ordering parts soon, so I am grateful for your replies!

Here's the full scenario: Had the water pump / TB service done with a Honda dealer I know & trust ~5,000 miles ago, incl. plugs, etc. Shortly afterward the p0300 and 301-306 codes would pop up intermittently, so I took it back to Honda to warranty their work. No issues with coil packs, no PCM updates available, checked EGR valve / ports, etc. and could find no issue.

The CEL was coming on more & more regularly with those same 300-306 codes with no known common causes being the culprit (no, I have not over revved). Last night it gave the added codes of p0153 (Circuit slow response - Bank 2, Sensor 1) *and* p2a03 (Circuit range / performance problem - also Bank 2, Sensor 1). Visual inspection shows connectors are clean, no obvious fraying or shorting of wires or apparent issues with the harness.

I'm thinking that o2 sensor may have been the culprit all along but only found a couple threads on p0153 and next to nothing on p2a03 and would like to confirm with the experience of others. But hey, if one had to go, at least it's the easiest one to access / change!

Finally, Denso appears to be the OEM manufacturer and their part # 234-5010 corresponds to this Bank 2, Sensor 1, correct? I can't see dropping an extra $75-100 via Honda / Acura without purpose. Your thoughts, gentlemen?

Thanks for all of your help!

 

Besides the codes, is the car behaving any different?

 

OP, did the Honda shop replace your plugs? Check your plugs to be sure none of them are loose.

 

It wasn't behaving any differently until just recently.

There is now a noticeable "miss" occasionally as I'm driving -- you can tell it's "not hitting on all cylinders," so to speak. It's also a bit rough at idle (only until warm, then idle is fine) -- in fact the only time I've seen the CEL *flash* is occasionally for 10-20 seconds when the car is first started (only happened a few times).

Thanks again for any & all help / insight you guys can provide.

 

@nfnsquared missed your reply before I hit send.

They did change the plugs during the TB/WP service + allegedly reinspected everything when I brought it back due to the CEL to no avail.

Would a loose plug throw the A/F sensor code?

Thanks!

 

Bad ECT sensor maybe?

 

What does that mean? Did they actually go back, remove all the coils and check the plugs? I doubt it. Ask them.

Don't know, but it would and has throw/thrown mis-fire codes.

But it could very well be a bad O2 sensor, they have been known to go bad.

 

If they really did check the plugs and coils, then it might one of these sensors...

 

I'll have to look at the work order again, but I believe they just pulled the connections on the coil packs one by one to rule those out as an issue, but don't remember if they actually checked the plugs themselves.

IIRC, they also cleaned out the EGR valve. I'll let you know on both once I'm home.

Either way, I have a simple OBD-II code reader en route along with the front o2 sensor, which will allow me to more easily diagnose / duplicate the codes and narrow this down.

Any other thoughts from around the community?

Thanks!

 

Ok, here's the recap via Honda's paperwork:

I was told the EGR valve was cleaned out as a result of these findings. Bad gas was originally suspected. Although I always use premium, I did have to get gas from a highway gas station that wasn't brand name on a road trip just before this, but put multiple fresh tanks of Shell gas + Heet in the tank since then.

Also seems to me like a valve adjustment would've been recommended when I was getting the 105k service done, but alas...

Keeping in mind there are 2 codes now both pointing at the front o2 sensor in addition to the misfires, am I nuts to change out that sensor as the most likely culprit or what?

Thanks.

 

By the way, it has started flashing the CEL for ~10 seconds every time I start the car up as of today (3-4 times). Not good, but perhaps provides some further insight?

The OBD-II code reader should be here in a few days. In the meantime, I'm becoming more + more wary of driving it...

 

Well, fuck...

Checked the plugs in the front bank, all was well, so I thought 2 codes point to this o2 sensor, I have a replacement here, let's try it.

Installed the Denso 234-5010, reconnected negative battery cable & restarted. Still a bit of a rough idle, for 30-45 seconds, CEL flashed for ~10 seconds and then went off. The idle smoothed out & I thought, great! It was the sensor all along.

Then I noticed smoke coming from under the hood.

When I popped it, it was coming from the area of the o2 sensor / cat, but I couldn't pinpoint it. The o2 sensor itself was also very hot, but duh, it's coupled to the cat.

I am about to just tow this thing to Honda & bring plenty of lube.

How did I manage to fuck up a simple o2 sensor install?!

Thanks in advance for any insights.

 

LoLoLoL @ myself -- once the PB Blaster & any residual grease from my hands / the process burned off, everything seems to be just fine -- She seems to be running just fine after ~50 miles of spirited driving.

I'll keep you posted, but it looks like the o2 sensor swap solved the problem!

Thanks...

 

Have you check your valve clearance? I have seen loose valves cause a intermittent misfire And how shortly after your timing belt service did it start to misfire? Maybe the timing is off a tooth you never know

 

After 350+ miles with no issues after the o2 sensor swap, pretty much the same symptoms have returned -- flashing CEL for ~10 seconds right after being started, rough idle + the occasionally felt "miss" (although these seem to be fewer / farther between with less of an overall loss of power feeling of sluggishness.

I have not been able to pull the new codes yet.

@ 3RDGENTL757 - Perhaps the valves do need adjusting? (my untrained ear hears a bit of the telltale click-click-click that may indicate it). Timing off a tooth feels like more of a long shot as it seemed to run fine for quite some time after the TB/WP replacement, but I appreciate the ideas to work from.

Is there anyway to confirm a valve adjustment is needed before dropping $300-400? I have ~118,500 miles on it.

I will report back once I've pulled the codes again to provide further insight.

 

Why are you putting HEET in the tank...?

 

Valves are supposed to be adjusted at every service if they are noisy or at 105K, then every 60K thereafter along with the TB & Waterpump

 

IIRC, I have yet to hear of any 3G TL that threw a code due to mis-adjusted valves...

Even at 105K, information provided by those of us who have done a valve job show them to be only 0.001" out of spec, if at all.

 

Latest Update: The only codes being thrown now (in this order) are misfires -- p0304, p0305, p0306, p0300, p0302, p0301, p0303.

Does the 4-5-6 sequence point to / hint at anything particular?

@alexb92 - Heet was recommended based on the original bad gas diagnosis. It actually made the light go off initially shortly after being added, so I ended up running 2-3 bottles through total over several tanks, thinking there may've still just been residual condensation causing the problem -- to no avail.

@csmeance - If the valve adjustment is needed anyway, I don't mind to make the investment. I love this car & will be keeping it for some time. But it would naturally be frustrating if after $100 on an o2 sensor + another $300-400 on a valve adjustment the car is still throwing misfire codes that even the dealer shrugs at & says, "I dunno..."

The EGR valve would throw a code, right?

Since this manifests most clearly at idle on a cold start (even flashing the CEL when first started), I took the EGR valve off + looked at it. There were no obvious chunks of carbon / gunk, but I also didn't see at all where it would spring "open" or be stuck open, as there didn't appear to be any moving parts whatsoever on the "valve".

Should I look at the EGR ports / runners under the cover on top of the engine next?

Once again, I truly appreciate everyone's help here. I feel others will come across this thread & ultimately be able to reach a resolution + save some frustration when facing a similar issue in the future as a result of our efforts!

 

Are you sure it hasn't been a victim of an over-rev?

 

@nfnsquared - An over-rev is out. I've personally had the car for nearly 22k miles and am the only driver. It's only been near redline maybe 2 dozen times since I've owned it for the past year. I do not drive it hard or ever rip through the gears with hard shifts.

What I can't figure out is -- Why was it running like a top for ~350+ miles right after the o2 sensor swap(?!) That, to me, would seem to rule out bent valves or similar catastrophic issue. That was a road trip, though, never stopping long enough for the engine to completely cool vs. the stop / start and cool off of around town driving, going to work, etc.

The issue seems to arise most prominently on a cold start. That keeps leading me back to EGR valve, ports or something similar -- even though it's not throwing a code. Does that make sense or am I just way off base?

Is there a way to test the EGR valve component itself? i.e. Is it possible something is wrong with the EGR valve internally that would create these symptoms?

All I could see searching the EGR threads here had to do w/ cleaning out carbon, replacing it entirely, etc. There was nothing I found on testing the component itself and I'd like to avoid just randomly replacing things + crossing my fingers. ;-)

Thanks again.

 

Just as a heads up, I have not forgotten or abandoned this thread & the misfire still exists.

This was just postponed by the drunk driver that hit me + the ensuing 5 week saga of insurance claims + repairs...

That's a thread in & of itself.

I'll be back here soon to work this out. Just keeping the community posted ;-)

 

Sorry to hear about your accident.
I'd vote for valve adjustment. Here's why: When the engine is cold, valve clearance is at its maximum, but when cold, the EGR system is completely shut off. Also, you have no EGR related codes. If the timing belt was off you would have known already.
Question: Did they install a new alternator (serpentine) belt? Some aftermarket belts have excess metal content, and can cause random misfire codes (there is a TSB for other Honda products for this). You can try running the engine with the belt removed to see if it still acts up (you will have no power steering). Good luck!