High pitch sound cuts out about 40 seconds after startup.

[120 New Jack]

Hi guys, I hope you can help diagnose a high pitch noise that begins at startup and cuts out at the 45 second mark in the linked video. Without headphones you can only really hear it when it cuts out. I don't think this is a normal sound and it may have been this way when I bought it. I started paying close attention to sounds while troubleshooting the infamous bank 1 420 cat code.
I couldn't find any other threads that dealt with this but if there is one please drop the link and I'll be on my way. Thx!

 

[Bisho]

Brake booster shutting off? Its not a 100 series, but that's my guess.

 

[120 New Jack]

Aw crap.. can the mod move this to the GX GXOR forum?

Sorry guys

 

[Jstawgn]

Probably Secondary air injection pump.
Most already bypass this. Eventually it would cause CEL and limp mode.

Secondary Air Injection Bypass Kits | Hewitt Technologies

Hewitt Tech is the Home of the Original Secondary Air Injection System (SAIS) Bypass Kits for Toyota & Lexus vehicles. These kits offer a cost effective DIY solution for the failure prone SAIS. Common codes include; P0412 P0415 P0418 P0419 P1441 P1442 P1444 P1445 P2440 P2441 P2442 P2443 P2445 P2447

hewitt-tech.com

 

[120 New Jack]

Bisho thanks for the info and heads up. I'll check into the secondary injection pump, thanks for the link Jstawgn.
Gonna repost this in the proper GX sub forum.

 

[120 New Jack]

Just saw this thread was moved. Thanks Mod!

 

[120 New Jack]

I forgot to include that this sound doesn't occur if I let it get to operating temp then turn it off for a minute then restart.

 

[Jstawgn]

I forgot to include that this sound doesn't occur if I let it get to operating temp then turn it off for a minute then restart.

This confirm air injection issue. They only run on cold start to help speed up catalytic converter to heat up.

 

[120 New Jack]

So

This confirm air injection issue. They only run on cold start to help speed up catalytic converter to heat up.

The link to the Hewitt tech site explains quite a bit. Definitely seems like this could be causing my cat troubles.

 

[120 New Jack]

Jstsa thanks for the help man. You may have saved me replacing a manifold.

 

[120 New Jack]

I'm now up to speed on the secondary air pump location, the diverter and both check valves. Hopefully I can find some time tomorrow to hear if that high pitch noise is coming from the driver's side check valve way in the back behind the intake manifold. I like the simplicity of the bypass but aren't sure that the bypass will fix my issue. It seems the SAIS is known to fail but I'm not getting any codes specific to that just yet, only a 420 low cat efficiency and fluctuating downstream O2 sensor voltage. I swapped the sensor already to no avail.

Even if the check valve is faulty and responsible for the noise, could it be responsible for erratic o2 voltage reading on just the downstream bank 1 sensor which is causing the 420 low efficiency code? ...Does the secondary air injection pump continue to run or does it turn off after it's at operating temp??

 

[120 New Jack]

Took another listen today to see if I could nail down the exact location of the high pitch noise and cut out at around 40 seconds. Sounds like it was somewhere under the intake manifold where the SAIS is so I removed the intake manifold to see if I could find anything obviously wrong. All the wires and connections look good, but I did find a rodent nest up in there.

 

[120 New Jack]

Decided to replace everything while I have the intake off. Found a really good tutorial video that I linked below. As of today the parts cost close to a grand, but that's for OEM stuff. The video has links to all the parts needed on Amazon in the description.

I could've cut the cost in half with an aftermarket pump but several reviewers claimed failure after several months so ordered the OEM part. I'm hopeful this fixes the noise and the cat efficiency code but I still might need to replace the exhaust manifold/cat anyway for the efficiency issue. I also found a leaky O-ring on an injector so will probably replace all the rings while I have easy access to the fuel rails.

It sucks but at least it'll be back to its original state. I've seen mention that the pump has a filter inside which is known to degrade over time. If that's the case I'd imagine the foam has to go somewhere downstream, wonder if that can foul a cat over time? My filter was gone so I'm considering doing the external filter mod and removing it from the new pump when it arrives, not sure if I want to do that yet or just let it go.. I plan on keeping this vehicle forever so I might. Dunno..

I'll keep you guys posted once I make more progress.

 

[120 New Jack]

Progress. Having a low-rise 1/4" socket wrench and a 10mm socket cut down to be a shallow socket will let you get to the check valve mounting bolts. ..I don't recommend removing the rear coolant bridge to access the check valves as it involves many unnecessary steps. Getting to the ones for the exhaust manifold injection pipe was a PIA too.
Now that the check valves are in I can put in the rest of the new air injection parts and get the intake back on. New seals for the intake and fresh injector rings.

 

[CarGuyCarl]

Why not just bypass it with the Hewett kit? I was getting the same sounds for months until it finally took a dump. Now bypassed with over 2,000 miles on it since. Seems like a lot of work for little gain. But you're already in there I guess!

 

[120 New Jack]

I was considering it but thought that maybe the failed secondary air injection was allowing air into the driver side exhaust manifold and possibly causing the bank 1 O2 sensor 420 code mentioned earlier. I wanted to rule out everything before having to actually replace the manifold/cat combo.

 

[120 New Jack]

So everything is back together without major issue. I had to use a screw clamp to fix a small coolant leak on the rear heater core hose but otherwise it went back together fine. While I had the intake off I carefully cleaned the carbon from the intake runners and replaced the O-rings for the injectors. New intake gasket and rear coolant bridge seals as well.

Unfortunately the high pitch noise is still there, so the air injection system parts (pump, diverter and check valves) don't seem to be the cause of the noise. I used all new OEM parts so I'm fairly confident it's not a new component that is defective, at least I hope so 'cause the parts (especially the pump) were stupid-money. Maybe it's a pin-hole in a vacuum hose? I replaced the vacuum line that runs from the bottom of the intake to the solenoids that control the check valves so that one should be good. I'm going to try disconnecting that hose from the solenoid pipe and clamp it. If the noise is gone then one of the remaining down-stream vacuum lines is bad. They other hoses were all pretty stiff when I was disconnecting them.

As far as the 420 code I'm going to try an O2 spacer. I really think it's dumb that something like a bad cat cuts out my VSC and A-TRAC capabilities. I consider that a safety issue and unnecessary. Last year when I was plowing I got stuck in a ditch because of this and had to use a traction board to get out. I have a stationary plow that I mount to the rear receiver and plow in reverse.. Ever since I've kept my scantool in the vehicle so I can clear the code and regain those capabilities long enough to get out of trouble. I also ran 2 treatments of Cataclean through to no avail, lights still on.

I'll update once I install the spacer and run it for a bit.