Another 2nd Gen P0333 thread. Not Rodent damage.

Hey guys thought I'd post up my experience here as it seems to differ from many other members. Ever since I bought my 2013 Tacoma 4.0L (about 18 months ago) it would set a P0333 code on rare occasions. Normally I'd just clear it and I was good to go for a month or so...

It recently started tripping the CEL and code much more frequently, so I decided to tackle the project of digging in and repairing the "rodent damage" so many others have experienced. Pulled the intake manifold and all associated stuff as per many other posts, and finally got eyes down into the "V" where the knock sensors live. Only to find the wiring looks fine. P0333 is for the bank 2 sensor, and the connector looked perfect, there was a small amount of rodent evidence in the "V" but no obvious damage on the wiring except, oddly enough, a small amount of seemingly cosmetic wire damage to the bank 1 sensor wiring.

I had already bought a new connector and sensor, so because of the lack of damage to the bank 2 connector and the actual damage to the bank 1 connector, I decided to replace the bank 2 sensor plus the entire knock sensor harness. I returned the single connector, and bought the whole harness.

This is where it got tricky, because it's fairly easy to pull the connector out and repair the existing harness, but replacing the sensor itself as well as the harness means I had to get in there deeper. As most know, per Toyota FSM, in order to remove the coolant pipes, you have to remove the heads (not gonna happen). So I did a little more research and found some guys online were actually cutting the bracket that holds the 2 coolant pipes together in order to remove the 1 big pipe. After much deliberation and trying to figure out another way, I decided to go for it.

I cut the brackets using a hacksaw blade held by hand (no room for an actual hacksaw), pulled the coolant housing off the front of the motor, and removed the big coolant pipe. It was actually much easier than I anticipated... and now, if I ever have to get in there again, it's much easier to do. From there I popped in the new sensor (SUPER easy once the coolant pipe is out of the way) and replaced the harness. It plugs into another connector located at the back of the bank 1 head (a little tricky but not super difficult to get to).

At this point I replaced the coolant pipe O-rings and re-installed everything with new gaskets on the intake and plenum. Also quick side note: because I cut the brackets holding the 2 coolant pipes together, I took a big hose clamp and re-clamped them together to avoid potential vibrations between the 2 pipes.

With the repair now complete it's just a waiting game to make sure the light doesn't come back... So far so good! I'm assuming the sensor itself was the main problem, but I wanted to replace the harness while I was in there just in case. It's been a few days now and no CEL at all...

 

Nice Job.
I too would probably have cut the bracket on MY truck.
I’m not pulling the head unless the head itself needs to be pulled. (At that point, I might consider a used engine)

Thanks for the post, and for the tip.
I can’t say I have ever heard of someone cutting the brackets, until now

 

Yea I never saw a post here on TW saying to cut the brackets, that was a YouTube trick lol. So figured I’d share here.
The way I see it, I plan on keeping this truck for the foreseeable future, so if I ever need to get in there and replace the sensors or deal with the wiring again, it’s easy to access now.

 

Crappy news today, CEL popped back on. Same code P0333. Brand new sensor and harness.
Anyone have access to a wiring diagram that shows where the wiring goes between the jumper harness and ECM? I’m suspecting I’ve got wiring issues elsewhere.

 

This should get you where you want to go.

 

Thanks… so it looks like there are no other connectors or anything between the mini harness and ECM.
Hmm. Gonna have to take a closer look at the main harness…
ECM is inside the cab behind glove box correct?

 

3 total

The K2, K1 (at sensor), the EE1 (between senor and ECH, and E5 connector. (At ECM)

 

Yes.

 

I'm in the same boat now. got the PO333 code and wondering which steps to take. toyota wants $5700.00 for the sensor repair. my truck is worth maybe $7800.00. I'm willing to try the repair but seems very difficult and time consuming.

 

FWIW had a bad sensor with good wires. Here's my experience on this problem:

2007 Tacoma. I had an intermittent Driver Side Knock Sensor code that would occur for a day or two at a time over a 2 year period. Infrequent, about every few months or so. I researched the problem, considered the fix, and decided it was tolerable as it was so infrequent. I typically drive about 100 miles a week in the truck. Fast forward to late this summer and the error code had rapidly become static; the dreaded tear down was inevitable. I purchased an OEM repair harness expecting rodent damage and started the teardown early one sunny Saturday.

When I got the manifold off I was surprised to see that, like the OP, there was no noticeable wire damage. I was able to unplug both knock sensors and test continuity and they were both good. I called the local NAPA and they had OEM Denso knock sensors on the shelf. $130/each as I recall. I was able to get the old one out using a swivel end ratcheting combo wrench. Definitely a pain in the ass and, in hind sight, it must be quicker to make the cuts to remove the big coolant pipe. It took about 30 minutes and a brief loss of sanity to get the harness plugged in and the mounting bolt tightened. In my mind, getting the passenger side one out is impossible with the coolant pipes in. I did NOT replace the wire harness as it turned out that I bought a wrong one. They changed them after a couple production years. It's been about three months and the light has stayed off. Including the time up to NAPA I had about 6 hours in it.

 

That’s what is frustrating, I replaced both the sensor AND the harness. Still getting the code periodically. Also, I get a noticeable pinging/knocking sound from the drivers side of the engine as well under moderate load occasionally. I suppose I could have gotten a bad sensor, but I haven’t had the motivation to dig back into the engine to find out.

 

That's understandable.

It's knocking while it's in Limp mode? I kinda figured that in limp mode it pulls timing and adds fuel to a point that preignition become extremely unlikely. I'm sure that's a telling symptom for someone that knows more about this than I do. Good Luck.

 

I get the pinging whether the code is current or not… all intermittent. One day I’ll get frustrated enough to pay the dealer to take a look at it. But that day isn’t today lol

 

Styx586 your 01 is awesome.

 

Thanks! I wish I still had it…

 

I had intermittent p0333 as well, replaced the affected sensor and the wiring assembly with new oem parts. I had the heads off too, expecting to find rodent damage, but didn't really see any. No codes since though, that was >2 years and >20k miles ago.

Sorry this doesn't help, but make sure the connectors are properly clicked on, and maybe you need an oem sensor? (My old one tested fine with a multimeter, but was throwing codes weekly.)

These sensors, their location and their use of rodent-food wiring, are probably the worst design shortcoming of these engines.

 

I think you’re right about needing an OEM sensor. I replaced with an aftermarket one.
Also yes, terrible design choice.