2.7 L Secondary Air System Gives Engine Light after Replacement

Well you can if it makes you feel better, but replacing a fuse that isn't blown doesn't help anything...

Take the lid off the pump and see if the air filter inside is coming apart and blocking the impeller from turning. This is a common issue.

 

The issue is that I replaced both the pump and the valve, they're both brand new. I even removed the filter and installed a Uni filter I had for the old one.

 

Did you inspect the fat hose from the pump to the ASV?
Check all wires and plugs for damage and make sure they are plugged in properly.

Then you need to start checking the remaining items on the list in post # 21 and # 22:


P2441 Causes:

Pressure sensor detects no pulsation of exhaust gas despite ECM commanding Air Switching Valve (ASV) to open, while engine running (2 trip detection logic)

•Open or short in ASV circuit
•Vacuum hose (ASV - pressure sensor)
•Air injection hose
•Pressure sensor
•Pressure sensor circuit
•Air Injection Control Driver (AID)
•ECM

P2445 Causes:

Secondary air pressure less than 2.5 kPa (19 mmHg) despite ECM commanding air pump to turn on (2 trip detection logic)

•Open in air pump circuit
•Air injection system piping
•Vacuum hose (pressure sensor - air switching valve)
•Pressure sensor
•Open or short in pressure sensor circuit
•Air Injection Control Driver (AID)
•ECM

 

OK don't be offended, but did you check the fuse for the Air Pump?

50 ampere fuse in the engine compartment fuse panel, Labelled as 50A A/PMP. When you check the fuse use a mutimeter or a test light. Your eyes may betray you.

This is what supplies power for the Air Injection Control Driver which powers the pump and ASV. If you don't have that it will never run the pump or open the ASV.

 

I doubt the fuse is the problem, it's in there and it's functioning. Even tested with a multimeter on 200 Ohms and gives out 00.3. Albiet I'm not good with a multimeter but I know it works.

 

And checking the wires, there doesn't seem to be a cut or a snag or even a loose connection. Everything is connected and snug as it should be. I'll check the hose and let you guys know what I found.

There's only the pressure sensor which doesn't give any codes as of yet so we're clear. Then the AID which I'll look more into.

 

In case you don't know where the driver is, it is behind the ABS Unit on the passenger side fender well area.

The pressure sensor does cause codes. Did you read the trouble sections above? A defective pressure sensor or wiring could cause both of these codes.

P2441 Causes:

Pressure sensor detects no pulsation of exhaust gas despite ECM commanding Air Switching Valve (ASV) to open, while engine running (2 trip detection logic)

•Open or short in ASV circuit
•Vacuum hose (ASV - pressure sensor)
•Air injection hose
•Pressure sensor
•Pressure sensor circuit
•Air Injection Control Driver (AID)
•ECM

P2445 Causes:

Secondary air pressure less than 2.5 kPa (19 mmHg) despite ECM commanding air pump to turn on (2 trip detection logic)

•Open in air pump circuit
•Air injection system piping
•Vacuum hose (pressure sensor - air switching valve)
•Pressure sensor
•Open or short in pressure sensor circuit
•Air Injection Control Driver (AID)
•ECM

 

Ok a couple problems have happened that I thought would clear the codes. One of the nuts went off from the valve connecting to the pipe that leads into the intake manifold. Got another nut and added thread sealant to them and looks like they won't be coming off any time soon.

Then the new hose for the pressure sensor went off of the valve causing fuel fumes to come out. Grabbed a couple of hose clamps to hold it into place. Done.

Then I drive all day after clearing the codes yet again, all good. Then just today, scanned for any code and there they are again! They just won't get away and everything is working. I don't understand!

I'm getting even more stressed out!

 

How do you know everything is working. Something is wrong and you just don't know what it is.

The biggest part of troubleshooting is knowing when you are over your head.

Is the pump actually running when commanded?
Is the valve actually opening when commanded?
Is the pressure sensor actually signaling the correct pressure?
Is the Driver actually telling the Pump and Valve to operate?

Some checks without an intelligent tester:







If these pass OK then you need to get a shop to do an active test with the intelligent tester.

It seems like the best way to isolate your issue would be a dealer or a shop that has an intelligent tester, so they can actually activate the system as needed to get voltage readings and pressures.

 

I might have missed it, but have we confirmed the Pressure Sensor is Good?

 

Pretty sure the answer is no.

 

Nope.

 

Hey OP what was the fix for this ?

 

OP has been gone for 3 years; I guess it didn’t work out

 

just adding my experience with this issue... the reed valve in these is prone to rusting/corroding shut in the south where I live. I went a long time with this system not working and accompanying CEL codes.

A couple months ago I was doing some other un-related maintenance and thought what the heck....pulled the main hose between the air pump and the valve body, squirted some WD-40 into the valve body where you can actually see the top of the reed valve and let it sit over night. The next time I cranked it I noticed the cold start sounded much different. I erased all the CEL codes and these specific codes did not come back, but the P0420 code did. I'm not saying this fixed my issues, but it didn't hurt anything either.

 

Hey if you’re next to your truck do me a favor and tell me where the hell that stupid vacuum line coming off the ASV goes. Can’t find a schematic or diagram anywhere. It must’ve snapped since I never took it off

 

Or where the flying fuck is this ominous pressure sensor lol

 

it is the manifold absolute pressure sensor listed in the diagram above

 

Here’s the thread I got that from btw

https://www.tacomaworld.com/threads/engine-bay-guide-for-the-2tre-fe-2-7l.534478/

 

Strongly recommend this product:

https://hewitt-tech.com/product/secondary-air-injection-system-bypass-kit-gen-2-plug-play/

Be sure to read the instructions & caveats carefully before buying, it can be a little bit extra complication & cost if you are trying to bypass an SAIS that has already started throwing codes.

Note that the Hewitt Tech product is "for off-road use only."

See also this TW thread w/ more info on SAIS issues, as well as other peoples comments & recommendations on the Hewitt Tech product:

https://www.tacomaworld.com/threads/secondary-air-injection-system-help-p0418.794748/