I installed a relay bypass (without blockoffs) from Jeff Cole after getting P1441 and P1444 codes. Was able to get the valves closed, I thought, by warming engine, turning off, key to on, clearing codes, then restarting. The other week the codes came back so reset again and looked at my setup. Thought maybe a bad connection at starter relay so reworked that, but they came back again today. My splices are soldered and insulated so not an issue there.

Has anyone experienced similar and had it solved by blockoffs? Would hate to spend another $50 and hours of time on them only to have it recur again. It just seems weird that valves would seal fine for weeks-months and suddenly throw a code again.

Other option I was thinking was that maybe the resistor is on the low side of tolerance so just enough to make the ECU think it was warm enough out to want to run the pump. Seems to be a pretty simple circuit, the vehicle start relay triggers the bypass relay to send the THA (air temp sensor) circuit through a 4.7kohm resistor. Nothing in the manual but people online say the pump wont run below 40*F, and 4.7kohm is right on the cusp of that. So maybe changing out the resistor for higher ohms would be a simpler fix? Edit: other consideration is that it has been pretty cold both times it happened which might be affecting the resistance?



My V8 is 10/06 production so shouldn't be affected by whatever was bugging the '08s+.

i actually had this happen to myself recently, i installed the slyfox bypass kit (w/o blockoff plates, as i had a p2445 i believe) this was back in march. I got the codes for p2445 come back in november and cleared the codes and recheck the relay in the fuse box all was fine after clearing it though and have not showed up since.

Good to know I'm not alone in it. Has anyone out there had a code reoccur after installing a bypass, with block off plates?

Guess occasional recurrence isn't a huge deal compared to spending a grand on parts and a day changing them, but still... First time my code came back I was hours from home in the middle of nowhere towing a trailer to help a friend move another 4Runner. Last time it came back I went to clear codes after warming engine and my Chinese ELM OBD2 unit bit the dust. If it gave up the ghost one use earlier would've really sucked. Sometimes when you need your truck, you need your truck.

From what i've heard some other people have had the codes come back periodically. Luckily i always carry my scanner in the car so i can always clear them but after clearing them 2 months ago it has not come back.

I did email slyfox in regards to this and he said it will come back sometimes but with p2445 blockoff plates are still not required.

Hmm, I don't understand why that would be the case, unless the system cycles itself every x number of starts or something regardless of air/water temp to check for operation. But that seems unlikely. Wish there was more info on system operation in the FSM.

My codes came back again yesterday morning as I was leaving for work, seems to be getting more frequent. Frustrating.

I also plan on emailing him, just wanted to get some more data first. If it was just a matter of upping the resistance I could do that myself easily enough. Guess I'll prob just end up springing for the blockoff plates unless he suggests otherwise

Hey guys.....yall know those threads where people post "This post worthless without pics" or something like that
Here I go.... "This post worthless without CODES". The bypass isn't a Check Engine Light defeat. It defeats very specific codes. The plates defeat OTHER very specific codes as/if needed. Post up some codes and we can make sure we arent chasing our tails. There also is a Toyota software issue that is very rare but can happen(regardless of bypass). It should be extremely rare(mine has done it once in 5 years) if you get repeat issues, let me know and we will work through it.

Jeff he did post the codes when he started this topic, very first post in this topic.

I installed slyfox’s bypass as well. It was warm out, the ecu went through the appropriate drive cycles, no codes were thrown or pending at the time. Within a few weeks, the codes came back and continually come back until I clear them. However the truck is completely driveable with the codes thrown. Maybe twice in the last 15,000 miles has the truck gone into limp mode, which was easily fixed by clearing the codes again.

However, I no longer have that shop vac sound at cold start ups. The codes are easily reset with a scanner as well. Jeff told me I might have to buy the block off bypass kit as well, but it’s been over a year now and it’s never gotten worse.

My truck shows 0418 (secondary air injection system relay ‘A’ circuit malfunction) and 2445 (secondary air injection pump stuck off bank 1)


Sent from my iPhone using Tapatalk

Appreciate the reply. My codes are first sentence, top of page - 1441 and 1444, so valves stuck open. But they were registering as closed for several weeks of driving after bypass install, with no issues. I don't see why they'd be opening now, or why the ECU would start thinking at least, since nothing has changed and they shouldn't be opening at all anymore if ECU thinks air temp is cold enough, right?

Is this something a block off plate will fix? Or will I then just get codes for valves stuck closed?

Out of curiosity, why a 4.7k resistor, which is right around the resistance the ECU sees when air temp is at the 40* cutoff temp? Wouldn't it be safer to use something 6-10k?

Ah...I gotcha....You would be surprised(maybe not) at the number of people that get a bypass and then later on "have codes".......that have NOTHING to do with the AIP system. So I always have to ask. I have wasted a LOT of time with people and "codes" that are unknown
So yeah.....the bypass(any) wont defeat the sensors that check for backpressure that thus throw you into limp or show as "valve stuck open".
To fix that.....plates. Could be that you have a partially open valve that is JUST on the edge of being closed and randomly the sensors sense enough back pressure to trigger the codes.
4.7Kohms should get you about 17F.......(roughly per Techstream). Well under the 41F needed.

You guys remember.....I offer the bypass and the plates separate. Order what you need. Others.....make you buy both so they can say(did you install the plates?) MANY people don't need the plates, so you can get away with $48. Other NEED and must buy.....but it is Optional in the end.
The 0418 is not a bypass defeatable code. P0418 is if your pump is shorted or unplugged. I tell people if they have this they can sometimes "spin" the pump(have it work as normal to get to "sweet spot" on armature) THEN put on the bypass and it will never run again. This is one of those things that usually is easily fixable if you do EARLY......if you wait for a long time, it will just get worse and potentially unfixable. The 0418 is typically fixable, but not always.

For sure, you did make that clear when I bought the bypass, and nice to have the option. Just hadn't read of anyone having an experience like I have with it so wanted to make sure it'd be the fix before putting more time and $ into it. I'm away for the holidays but will hit you up for plates when I'm back around.

Do you mean his 2445 code on the above description?

If 0418 is the code for relay "A" supplying power to the pump it might be possible that the relay coil shorted or contact arced out and the pump isn't getting power and making pressure leading the pressure sensors to conclude that it's stuck, in which case maybe replacing the relay would solve it. Pure conjecture but seems plausible.

The 0418 comments are for @DZNUTS , he said he was having an 0418 code.

I've had the same codes recur 5 times AFTER having mechanic install the bypass kit and then a year later spending 3,000 at dealer to put in the Toyota system. It's in the shop now. 2007 V-8 Limited. Will report back whenever, if ever, I get rid of the codes and light-up dash.

What are your codes? We can help......but need to know what codes you have.