Thanks for all the positive comments! It is greatly appreciated and so many folks on this board have been incredibly helpful. Without this board and toyota120, a lot of my researching and subsequent build would have been infinitely more difficult.

Over the upcoming months I hope to post a lot more details on the why/how of products and methods used so as to 'pay it back' and to add a little explanation as to the thought process behind the build.

The electrical and cargo box projects are the ones I'm tackling over the winter and they'll be covered ad nauseum and probably in their own threads for other folks ease of use.

I haven't seen a lot in regards to this issue on 4Runners but occasionally posts pop up where folks have one of these error codes or experience a noisy/faulty air injection pump.

The following are error codes which can be remedied with a bypass module or the cheaper relay option:

P1441, P1442, P1444, P1445, P2440, P2441, P2442, P2443, P2444 or P2445

I had several CEL lights this past summer relating to stuck closed valves and air pumps stuck off. Tundras had a HUGE issue with failing/faulty pumps and Toyota decided to cover them under warranty. Even though 4Runners have the same systems and problems, Toyota decided they would not extend the courtesy to 4Runner owners.

Long story short - if you have any of those codes and need to pass emissions/want to clear the CEL lights or prevent even worse AIP (air injection pump) issues in the future, there are a couple options other than replacing pumps and valves which can run upwards of $3000.

These codes CANNOT be cleared with bypass:P0412, P0415, P0418, P0419, P1613, P1614

The two bypass methods are:

1. DIY Relay Method Runs about $40 in supplies.

2. AIP Solid State Bypass Module with block off plates. Was $200 when I got it but looks like price has increased (I think you have to contact the seller for exact pricing) Module link. The seller also provides about 14 pages of detailed instructions so as long as you aren't color blind and can solder it's a VERY easy install.

I know @superman3043 had this issue and used option #1. He was extremely helpful when I installed mine and had a question or two. Hopefully he doesn't mind me name dropping him here

I ended up going the second route. While it was more expensive I liked the solid state module and how clean the install would be. I'm in the process of adding a lot of wiring and a 2nd battery and really wanted the cleanest OEM look possible for the least amount of work. I'm sure you can make the relay look pretty clean but I just wanted a quick fix and to be done with it.

Install took about an hour and a half and about an hour of that was spent cleaning and re-looming everything to keep it factory looking.

**Quick background on what the bypass does/how it works. The air injection system runs a system check whenever you start the truck at a COLD start up. It checks the air temp via the MAF sensor and if the air temp registers GREATER than 41 degrees, it fires up the air pumps to pump air into the catalytic converters to warm them up faster and prevent unwanted air pollution. So, the bypass intercepts the temperature check signal and tells the air pump system that it does not need to run. For emissions testing the computer just checks to see that the system is running its protocols so it will see that it's running standard checks and pass (assuming there aren't unrelated emissions issues).

Now on to the install pics.

First step is to locate the MAF sensor wire.



Unplug the sensor and take the wiring out of the loom. There should be 5 wires:

You can ignore the Brown wire and white/red wire as those will not be tapped into.

Here's the bypass module and wiring diagram:



*edit - need to add a pic of the diagram here...

The wires soldered and ready for heat shrink tubing:



Re-wrap with electrical tape and re-loom. Even though I staggered the wiring taps with clean solder joints, the OEM loom was too brittle and narrow to house the modified harness so I added larger loom to the center section to keep it protected and somewhat factory.





The block off plates are near impossible to get a decent picture of but following the instructions is very straight forward. Just loosen the 2 nuts on each manifold, slide the plates in and re-tighten.

I need to get an updated picture of the starter relay wire (purple wire). Its function is to send the signal when the starter fires up. Basically if you turn the key to accessory and don't start the truck for 5 secs, the module will no longer start the signal so the starter signal re-starts the module. You really don't need it if you get in and start your truck up right away.

Looks good Matt! Glad you got squared away. We're about to do another for my buddy that's getting intermittent lights and codes. So far so good on mine.

Thanks and good luck on his truck. With the bypass and block off plates I just passed VA emissions yesterday so it definitely works! Sometimes the block off plates will be needed even if you go the relay route. I installed the bypass but didn't have time to put the block off plates in at the same time. A few days after I thought it was fixed it threw CEL/VSC etc and put the truck in limp mode. Block off plates solved this issue.

These plates block exhaust from pumping up to the secondary air pump valves. This can trip other codes and potentially put the truck in limp mode. Just something to keep in mind if the relay fix is properly done but doesn't fix the problem.

I also think these same block off plates would be a viable solution for anyone using aftermarket manifolds/headers to keep the air injection system happy.

Got some pictures of the plates installed and uninstalled from underneath the truck that I'll post up soon.

Cool, thanks for the heads up.

Had a few folks inquiring about the wheel fitment and Konig Six Shooters so wanted to post up some better pics. @typehxr1







And some more up to date pics from some snow wheeling a few weeks back:







Found some fisher tracks - if you're not familiar with them they're basically giant weasels. Really nasty critters.



Mmmm. Salty.

Managed to get a major step in my wiring project wrapped up. A lot of folks add accessories and tap into OEM harnesses and use 'add a fuse' etc. That works but I'm a big fan of leaving the OEM harnesses do the job they were designed to do and add separate relay and fuse boxes to power all the aftermarket additions. With these boxes wired to my dual battery, the main starter will only be running the OEM systems and eventually, a winch.

Enter the Bussmann relay panel. These are IP66 weatherproof rated boxes that are compact and house 5 micro relays and 10 mini fuses. They come in a variety of configurations. I opted for the dual buss bar box so I could wire the relays upside down and have one buss bar for 12v power and the other for the ground. The box can handle a max 80A and each relay is rated to 35A.

I built two boxes as I already have 6 relay driven accessories and want room to grow. Between the 2 boxes I'll have 10 relays and 20 fused power leads (10 of those will be used to fuse the relays). Everything was color coded to match the interior harness and leads from the switches and to the accessories. One box will be wired 'hot' with full time power while the other will provide power while the truck is on.

Anyways, figured I'd post up some details since I haven't seen these on this forum quite yet. It's definitely overkill but half of the build is learning new skills/abilities and trying new things along the way.

Ready to start:






My helper was too preoccupied to help....


The assembly process is basically a lot of wire stripping, crimping, and soldering.


Crimp and solder the fuse to relay 12v jumpers:


They plug and 'click' into place:


My roommates box completed (for his Jeep). He still has to decide his plug configuration:


From there I made my two boxes and added flexwrap and heatshrinking to bundle the wires. Each bundle contains colormatched 18 and 12 AWG wire. All GXL auto wire. The 18 AWG is the trigger wire which runs to the console switches. The 12 AWG is the accessory power wire which will run to the lights, horns, air compressor, etc.





One crimped and one soldered. Apply flux to the wire tips to promote the solder penetration.



Ready to snap into the weatherpack connectors. The weatherpack plugs will make any future changes very simple. Installation will be just installing harnesses and running the loom instead of a bunch of under hood and under dash solder/wiring work.



And the finished products:

WOW and I thought I got a little OCD about my wiring the last time I rewired it.

Can't wait to see this when it's finished.

haha. spent so much time laying out the schematics that I wanted this to be a one and done install. I spent enough time wiring under the hood and dash while building the mustang that I knew I wanted to be able to do 95% of the work inside at a bench instead of upside down with a flashlight.

I don't use the little flip up tray next to the shifter very much and the OEM cig lighter is in a terrible spot given it's orientation. So I'll be mounting a 6 switch panel in place of it with Contura V switches from OTRATTW.com . You can tell them what design you want and they'll customize however you want.

Initial fitment:



Final fitment mockup before bondo and paint:



Started to build the wiring harness for the switches. These are SPST switches with red backlighting. Wiring is pretty simple. Ground gets jumpered to both light grounds and daisy chained along. Then there's a pin for illumination, pin for +12v and the switched pin that pushes power to the relay or accessories.



The switch output wires will be 18AWG since they won't carry much current. The 12v power feed, ground wire and illumination wire will all be 12AWG with 18AWG tails going to each switch socket.



Left a little room in the harness for adding in seat heaters down the line (although they may just get wired independently depending on power consumption).

Ground wire done - jumpered to grounds for both lights (light for text and light for when switched on):



Illumination and power lead done:





Relay trigger wires done, waiting on plugs. Don't forget to bench test - they sell 120v to 12v inverters that are extremely handy for testing all the wiring.



Wired in the plug for my still undecided switch...thinking it will be power switch for the ham.

Forgive me if this is a dumb question but I'd still like to know. What do you plug those connectors into? I have a couple of additional switches but I'd like to do more but I'd also like it to be much nicer than I did the last couple of times.

No such thing man! Those connectors will plug into matching connectors for the wiring harness that runs from the engine firewall to the console area by the shifter. Then there will be another set of plugs which is where the switch panel harness will plug into.

I'm just making my own wiring harnesses so that everything is plug and play and any revisions or future additions can be very easily added.

Here's one of my many chicken scratch wiring sheets. more of the conceptual planned:

Quite thorough!

Whoa -- nice build! I've been eye'n the six shooters for my 08 Sport Edition (in silver as well), and I think your pics really sold me on the graphite gunmetal.

<- Also a Northern VA resident... You seem to like wiring, feel free to come help me install my TRS Quik-Retro's :P

Thanks Navin. The six shooters are great since they only weigh 20/21 lbs. and the graphite offers a bit of contrast over matte black wheels. Also nice that not many people have them! Konigs customer service is top notch as well.

If you want to check the wheels out in person let me know. Never done a retro before but always willing to learn something new or lend a hand if need be!