New Member...with a Problem

Greetings all.
Been reading posts for a while and enjoying them. Now I have one of my own.
Left the gas cap off my 2012 4.6L Tundra for several days until I found it. This set off several error codes. Once I attached the cap to the tank opening all the codes disappeared except for a p0412. From what I can find, this indicates a problem with the circuit of switching valve 'A' of the secondary air injection system. In full disclosure, I just replaced this valve (with a Dorman brand) about 10 weeks (1000 miles) ago. The old valve worked, but the air pump had failed and I decided to place the valve at the same time.
Today I removed the valve and checked the solenoid. Worked great on the bench. Next I measured the voltage on the wiring harness connecting to the valve. It measured 12 volts when I started the truck - with the harness disconnected of course. So now I'm wondering what the p0412 really means? Has anyone had any experience with this?

 

Welcome from NY.
No clue about you code issue, hopefully someone else will have the answer.
Try disconnecting the battery for about 10 minutes then connect it and see if the code goes away.

 

Thanks for the Welcome.
I have erased the code multiple times with a code reader and disconnected the battery for over an hour. Code returned each time.

 

If you can’t find the cause, you could try the bypass kit.

https://hewitt-tech.com/store/index.php?l=product_detail&p=82

https://www.tundras.com/threads/aip-diy-instructions.39555/

 

Welcome from the Texas Hill Country.

I am fortunate to have no experience with SAIS problems, but in your position, I would start here (or Repair Manual): https://autoservicecosts.com/obd2-codes/p0412

Simply checking for 12V at the valve, and bench test of the valve, sounds like incomplete trouble-shooting. Your PCM is still sensing an abnormal condition in the circuit somewhere (grounding side?)

 

Welcome from LA (Lower Alabama)! I'm unable to add anything helpful, but there are folks here that are pretty good at sending you in the right direction.

 

Welcome aboard from SoCal.

 

Welcome from Ontario Canada

 

Welcome from Ohio

 

The aftermarket parts are garbage for the secondary air injection system on the Toyota/Lexus vehicles. P0412 means the solenoid circuit inside the air switching valve does not measure within spec of the factory part, there is wire damage from the air switching valve to the air injection control driver or the air injection control driver is damaged.
We see lots of problems with the aftermarket valves, particularly the pressure sensors but most likely it is the aftermarket part causing the problem.
We have a few different solutions for our code like our V54H kit with a Valve Solenoid Pack addon but would highly recommended the Gen-II bypass kit for your particular vehicle and to never deal with it again. Please give us a call if you have any questions 844-307-7671 https:hewitt-tech.com

 

Dorman has a lifetime warranty on their parts. I would get a replacement. The bypass kits are slick but I'm all for clean emissions and SAIR does a great job of reducing cold start emissions.

 

I think I heard Paul drop the mic at the end of that post.

 

Well, I hope that isn't the way it sounded..lol There is just a lot of bad or confusing information out there about these systems. I always just try to share as much factual information from what we see and hear from our customers everyday.

 

Last year I replaced the PCV on my 2008 Acura TL Type S with a Dorman brand. Problem was fixed but my check engine light came on and stayed on. I returned the Dorman and replaced with OEM and the issue remained fixed and CEL went away. Dorman sucks In my experience.

 

No criticism here! Your answer was extremely knowledgeable and gave the OP a clear route to a solution!

 

Welcome from So Cal.

 

If you still have the old valve that you replaced sitting around.....put it back on a see if the code clears!