Brief whirring/revving noise at startup

[Backspin]

For the past few mornings, upon starting my 2006 4R (V8), I hear a loud whirring or revving noise, which stops after about 30 seconds. To me it sounds like an electric motor, perhaps powering a pump. Sometimes it starts right when the engine starts, and sometimes a few seconds afterward. It's duration seems to be 30 seconds, and so far I've only noticed it on the first startup of the day. It's noticeably loud, and definitely coming from the engine compartment. I've been searching for an answer here, but haven't come across the same description yet.

Any ideas?

Many thanks,
-Tim

 

[sonerick]

There's a vacuum pump that operates on start-up to make sure there are no leaks in the evap system. Maybe that's what you are hearing? I'm not too sure about the specifics, hopefully someone else can add some more info.

 

[settytb]

My guess is the electric brake booster...happens while driving around and using the brakes too.

 

[Backspin]

Something different today...I didn't hear the same noise, but I did get a check engine light and a VSC indicator lit, and a TRAC indicator lit on the instrument panel. I ran obdII diagnostic for the check engine light, and came back with two:

Current -P2445 Powertrain: Secondary Air Injection System Pump Stuck Off bank1

Pending -P2441 Powertrain: Secondary Air Injection System Switching Valve Stuck Closed bank1

I've searched for those code on this forum, but get no results. I'll do some web research, but in the meantime, if anyone else has had this issue, can you provide some insight?

Thanks again,
-Tim (Backspin)

 

[bytemaster0]

Something different today...I didn't hear the same noise, but I did get a check engine light and a VSC indicator lit, and a TRAC indicator lit on the instrument panel. I ran obdII diagnostic for the check engine light, and came back with two:

Current -P2445 Powertrain: Secondary Air Injection System Pump Stuck Off bank1

Pending -P2441 Powertrain: Secondary Air Injection System Switching Valve Stuck Closed bank1

I've searched for those code on this forum, but get no results. I'll do some web research, but in the meantime, if anyone else has had this issue, can you provide some insight?

Thanks again,
-Tim (Backspin)

This system is part of emissions control. It basically does exactly what it sounds like - it injects air into your emissions system so that it passes emissions standards. Here's a good read on it: Secondary air injection - Wikipedia, the free encyclopedia

 

[talonjade]

:wtf:

Good luck my man I hope you get it figured out!

 

[Joshelm]

I have the same problem with my 05 t4r v8. Aside from the p2441codes, I have 2 more codes that came up p1442 and p1445. But suddenly those codes disappeared on me while I m driving this ,the truck is running fine. Pls advise how did u solve your issues with ur truck. Thanks

 

[boondoggle]

Sounds kind of like this.

http://www.toyota-4runner.org/4th-gen-t4rs/120330-air-intake-pump-dead.html

 

[ChaosStarter]

Bytemaster got it.

When the system is working properly, you're hearing the air pump working. It only gets turned on by the computer on cold starts and it's only on for maybe 10 seconds or so for emission purposes.

The problem is that over time, moisture can get into the pump, and the pump sends that moisture through the valves, and they get corroded over time and begin to lock up, hence the codes. Unfortunately on the V8s, you have to pull the upper intake to get to them since everything is in the valley of the motor.

 

[Backspin]

I guess I'll just have to tolerate it...

Yes, it's the secondary air pump. From what I gather, its sole purpose seems to be to inject more air into the exhaust for a few seconds during startup to aid the catalytic converter in efficiency. I looked at the service manual, and indeed, the pump is located under the manifold, and steps 1 and 2 for the replacement are: "Drain engine coolant," and "Drain engine oil." Dang. You know it's gonna be involved (and expensive) when you see that. So, I just keep resetting the ECU with an app on my Android phone (Torque) and my Bluetooth-enabled OBDII reader. I guess that's pretty much all I can do for now.

Anyone here ever replaced this part (or had it replaced by a mechanic)? Is it as involved/expensive as I think it is (as in "substantial")?

Thanks,
-Tim

 

[Backspin]

I wonder if they use the same engine?

Just found a little more info, and it seems this is a common problem on certain Tundras and Sequoias:
Toyota Warranties Air Pump System - Reimbursement Available | Tundra Headquarters
If they have the same engine as the 4Runner, I would think this extended warranty would be applicable, yes?