lanalexus

Hello all,

I have browsed the forums periodically when I've had issues with my car (which luckily have not been frequent). I have relied on another forum generally for questions, but see that there is better response here and generally thoughtful responses.

About a month ago, my ES300 started throwing a CEL (I'm a little over 154k miles right now). It was intermittent and generally didn't seem bothersome. Then it started to accompany occasional misfiring symptoms while sitting at lights, which would also come and go. Note that during this period, I had a loose battery connection that would sometimes come lose to the point that when I'd go to start the car, I'd find that I'd have to jiggle the cable a bit to get it connected properly.

The issue became worse on Thanksgiving, as the car was chugging while driving so I pulled the CEL code: P1354. I did some research and tried cleaning and reinstalling the OCV closest to the front of the engine compartment.
That seemed to fix it for a few days, when the car began misfiring again. It was more frequent than before, but still would be fine for a few days then start up again.

I pulled the codes again when the CEL was active and they were P0300, P0302, P0304 and P0306. I had some work done on the car a couple years ago that I think included replacing the corresponding ignition coil, but I still need to check and verify. So I am not sure if that's what needs to be done or not. I did try cleaning the same OCV one more time to see if that would do anything, but it didn't

Additionally, today the car also reflects P1351 - note that the above codes and P1351 show as pending as of this writing (the CEL has been intermittent still, as has the apparent misfiring).

Any suggestions on where to start? P1351 coming into the mix makes me more concerned.

First thought was to replace the OCV completely (rather than just clean it with brake cleaner), and possibly the other one to see if that does anything. But welcome any advice.

Seems like the car is going downhill quickly. I could take it back to the Toyota/Lexus specialist I had do the ignition coil work for me, but given the multitude of CELs, I'm concerned they'll take me for a ride.

Appreciate the time.

crwys

If cleaning the OCV temporarily solved your problem and you were/are getting a code for the OCV I would definitely replace it. A failing ocv can also cause misfire codes that you mentioned.

lanalexus

One thing I saw some mention of and did not address when I cleaned the OCV was the filter. Could that also be causing problems? I see it listed in BearsLexus' post: https://www.clublexus.com/forums/rx-...ement-diy.html (the engines are the same for ES300 and RX300, correct)? I could not actually find a reference post on where the filter was until doing more research today.

Also, what is an easy way to find out which part number is for the corresponding OCV? There are two in his post and wasn't sure if there's an easy way to tell (aside from bumping that thread). Never mind on this part - scrolled further and found that for the one I tried cleaning already it's 15340-0A010

Pardon any ignorance. Having what has been mostly a reliable car until recently has me less informed versus previous cars that have required a lot more elbow grease

PFB

lanalexus

Feeling pretty confident on that one. P1354 is the left bank, closer to the radiator bank, bank 2... right? I've seen a few posts say bank 2 is the one closer to the firewall, but the majority indicate radiator side, especially for code P1354.

PFB

lanalexus

As a note, I disconnected/reconnected the negative terminal (which I also did during the second clean of the OCV over the weekend) yesterday afternoon and the misfiring stopped, at least for my commute home/back to work today.

I ordered new OCVs that will arrive early next week and will plan to install them and see if that helps with the issue for more than a few days. More to come.