2001 Tundra Knock Sensor (P0325)

This is my first post, was hoping to get some advice from more knowledgable car guys like y'all.
Bought a 2001 V6 Tundra a little over a month ago. A week after buying it had to get the head gasket and upstream O2 sensor replaced which hit my pockets pretty hard. Mechanic had it for quite some time as he was doing it on the side, but now after getting the truck back it threw out a P0325 almost instantly.
I would rather not have to spend another couple paychecks to fix it, so would like to do it myself. However, everything I've seen online seems to tell me that getting to the knock sensors under the intake manifold can be a huge pain, especially for a younger guy with limited mechanical experience like me. Would really appreciate any tips or tricks to deal with this, any and all feedback is appreciated.

Edit: This wasn't an issue before getting blown head gasket fixed, so maybe the mechanic didn't plug it in correctly or cramped the wire when putting the intake manifold back on? Not sure if that's a possibility, just throwing out guesses...

 

I'd be assuming the mech either didn't reattach the knock sensor harness, didn't snap it fully into place, OR broke off the detention tab on the harness OR similar harness mangling. But it's entirely possible he fucked something up and the engine actually IS knocking. Do you hear it knocking?

I would immediately take it back to the mech and have him fix. (I'm also surprised to hear it blew a head gasket, but that's another story entirely)

 

Now that you mention it, i do notice a faint knocking sound when idling and it gets louder when rpm goes up. Its like a unsteady ticking sound, is that sort of what i should be looking out for?
I’ll definitely contact the mech and see if he will fix it.
Also im pretty positive i bought it with blown (or about to blow) head gasket. I didnt push her hard in the time i had it, honestly never took it faster than 55mph or higher than 4500rpm. Think the guy just covered it up long enough to get rid of it cos it ran fine during the two test drives, but not even a week after buying it i had a mountain of white smoke from exhaust and coolant mixed in the oil.

 

Ticking sound is normal, the injectors are supposedly noisy on these trucks. I have a faint ticking constantly.

I just went and looked it up, should've done that originally. P0325 is "sensor malfunction". So it may be that the sensor is bad or got damaged in the process? Either way, if it wasn't tripping prior to this, the mech should be looking into why it's happening now. I wouldn't doubt if he needed to touch on that stuff while in there.

 

Looks like you have the 4.0 v6. I replaced mine on my 07 tacoma with 4.0 v6, it is a pain in the ass because of the coolant pipes that go over the knock sensors. Go to Tacomaworld forum and there are a few write ups on how to do this job on the 4.0 v6. If the mechanic forgot to plug the sensor in he will most likely still have to remove the intake manifold and get under those coolant pipes. If you go in to do this job you might as well get a brand new oem knock sensor and the oem sensor harness. Check out the write ups on Tacomaworld, there are two ways of getting to the sensors after removing the intake manifold. You either remove the coolant pipes completely or you can cut the tabs that hold the two aluminum coolant pipes together and that will give you some play with moving the pipes around and if you have small hands your can get under and remove the knock sensor and harness.
When you say head gasket did he replace both sides or just the blown side. Was it cylinder 6 that blew as this is the most common cylinder that these 4.0 v6 (2001-2006) that compromised the head gasket. Hopefully your mechanic used the OEM multi layer steel gasket as they were updated for the 4.0 engines.

Good luck

Rod

 

Ive actually got the 3.4 v6, the 5vzfe. Ive already seen on Tacomaworld the two ways you mentioned to get to the knock sensors, i’ll probably go with just cutting the tab. Also not sure which cylinder it was but i think he replaced both head gaskets. In the quote he mentioned resurfacing both heads so makes sense to think he did both gaskets.