A non-enthusiast's Tacoma build

I'm fairly certain the cause in my case is also a windshield replacement. It took time to show up, just like yours did. I didn't have the failed relay that you did though.

 

When it rains, it pours…



Gonna have to research this when I have time. Here’s hoping it’s nothing I can’t handle myself.

 

Following up. Nothing gets my blood pressure up like a (pending) CEL, so I didn’t waste any time trying to diagnose the issue.

The P0012 code that popped states:
Camshaft Position 'A' Timing Over-Retarded Bank 1
https://www.autocodes.com/p0012_toyota.html

Upon consulting the Library of Tacomandria (old threads), I found two likely culprits: the VVT filter, and the VVT solenoid itself.



VVT filter



From what I understand, this filter is designed to keep crud out of the VVT solenoid. With the P0012 error code, it stands to reason that the filter is either clogged or failed outright.

I located the Bank 1 (passenger side) VVT filter, which is most easily accessed through the front-passenger wheel well. I then used a 14mm socket and a couple extensions to remove the plug. The filter came out attached to the plug, which doesn’t always happen according to some reports.

It didn’t look especially dirty to my eye, but I opted to do a bit of maintenance while I had it in hand. I rinsed the filter out with gasoline, which isn’t the preferred method for addressing this part. Without a replacement filter on hand, it was the best I could do.

I reinstalled the VVT filter and torqued to 46 ft-lbs, which is the only torque spec I was able to find for this part.

It’s worth noting that accessing the Bank 2 (driver’s side) VVT filter requires removal of the alternator. Not nearly as straightforward as what I did.



VVT solenoid

Now on to the VVT solenoid itself. According to a couple sources I found, a sticky solenoid can cause a P0012 code. I also found a useful picture showing the indicators of a stuck/gunked up solenoid:

Off I went to pull the VVT solenoid. After removing the engine cover, air filter housing, and air manifold, I was left with this:



You can see that the Bank 1 (passenger side) and Bank 2 (driver’s side) VVT solenoids are very close to each other:



Since I was already in the neighborhood, I figured I should pull them both for inspection and cleaning.



While neither solenoid was as gunked up as the photo in the quoted post above, it was clear that the piston was slightly out of position when at rest. Without spares on hand, I once again did the best I could with what I had. Hosing both solenoids down with throttle body cleaner, including inside the enclosed end (near the electrical connector) seemed to restore full range of motion.

Reinstallation wasn’t too difficult, nor was reassembly of the other components.



Oil change and testing

After putting everything back together, I immediately performed an oil change. One of the potential causes of clogged VVT filters and sticky VVT solenoids is old, dirty oil. While my oil wasn’t past due, it was within 800 miles of my next scheduled change. When in doubt, swap it out.

I fired up the engine and had a very rough start. I then immediately got a P0306 code, which is for a cylinder 6 misfire.

F###. I thought my unreliable vehicle days were behind me.

Then I had a realization. Between all the crap I sprayed on the VVT solenoids, the gas I dumped on the VVT filter, and (stupidly) not disconnecting the battery before doing any of the above, maybe the computer was getting a little spazzy. Time to disconnect the battery for a bit, let it sit, and try again.

The truck started up just fine the next go around. Oil level was spot on. No error codes. Redlining it (in park) yielded no weirdness. An aggressive test drive, hitting 90 mph for a few seconds, was similarly fine.



Preventive maintenance

I plan on replacing both VVT solenoids and both VVT filters in the next couple weeks. While I’m comfortable handling three of those four tasks, I’ll save the Bank 2 (driver’s side) VVT filter for the dealership. Removing the alternator requires a level of technical know-how that makes me more than a little uncomfortable.

This is the first engine trouble I’ve had with this vehicle, and I have zero interest in it happening ever again. I plan on adding VVT solenoid and filter replacement to my maintenance schedule, with an interval of 100k miles.

 

Good to see you trying.
But I have to be honest. Unless there is an active code (not pending) or a drivability issue, I don't get concerned with pending codes.
P0012 is a 2 trip detection code. It has to see the issue happen 2 times on separate trips. And there is a reason for 2 trip. Because "not all problems are a problem" until they are a problem".
Things can just happen, and then they don't happen again.

Once every couple years, my truck will start up and immediately cut off.
It will start right back up and run fine for a couple years after that. Things "just happen".

I'd drive the truck and wait until the p0012 sets permanently.

 

Good feedback, @TnShooter. I’ve got a bit of a hair trigger when it comes to vehicle issues due to previous experience with my old F150, so I tend to attack anything that pops its head up. Better safe than stranded is my line of thought.

That said, do you think replacing the VVT solenoids and filters could cause fun new problems? My gut says no, but I honestly know very little about these engines.

 

Nope. The only issue it will cause is your wallet to be lighter.
Just make sure you get new seal washers for the filter bolt. Just to avoid any leaks. (They would probably fine reused. But might as well replace them too)

 

I've been searching for the sealing washer part number without any luck. Do you know what it is?

 

Good looking out, thanks @TnShooter.