Diagnostic Test?

[SurferRob]

I've had my 2011 SR5 for almost a year. I went out to the garage last night after it had been sitting for about 4 hours and noticed a "hum" sound coming from the back. I had never heard this before. It's the sound it makes right before you turn the ignition. I called the dealership and explained what happen and they talked to a TECH and the answer they came back with was it's a diagnostic test, something about the evap? Has anyone else noticed this? Just wondering.

Thanks
ROb

 

[westwind77]

I am starting to think this question needs to be a sticky on here. I fear if this question keeps getting asked and then someone actually decides to 'search' for it the large number of results may open up a black hole to which we all will be sucked into (well all except the Chevy truck drivers, they can survive anything).

 

[kmiller8821]

I've had my 2011 SR5 for almost a year. I went out to the garage last night after it had been sitting for about 4 hours and noticed a "hum" sound coming from the back. I had never heard this before. It's the sound it makes right before you turn the ignition. I called the dealership and explained what happen and they talked to a TECH and the answer they came back with was it's a diagnostic test, something about the evap? Has anyone else noticed this? Just wondering.

Thanks
ROb

Here are just 3 examples I found with the fantastic search feature.

We've seen this question once or twice (/sarcasm)

http://www.toyota-4runner.org/problems-warranty-issues/89506-4runner-buzzing-sound.html

http://www.toyota-4runner.org/5th-g...nd-near-back-wheels-when-engine-shut-off.html

http://www.toyota-4runner.org/5th-gen-t4rs/63923-noise-comming-rear-my-4runner-limited.html

It's NORMAL, btw. Also, that handy thing in the glovebox (aka "the owners manual") explains this in great detail.

Here's a quote, from the owners manual, page 22 (2010 4runner) "For Your Information" - The second bullet reads "Noise from under vehicle after turning off the engine". "Approximately five hours after the engine is turned off, you may hear sound coming from under the vehicle for several minutes. This is the sound of a fuel evaporation leakage check, and it does not indicate a malfunction"

Happy motoring.
------------------------

I am starting to think this question needs to be a sticky on here. I fear if this question keeps getting asked and then someone actually decides to 'search' for it the large number of results may open up a black hole to which we all will be sucked into (well all except the Chevy truck drivers, they can survive anything).

:iagree:

 

[Theslammer21]

they call it key off evaporative emissions check

1. Key-off monitor

This monitor checks for EVAP (Evaporative Emission) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the ignition switch is turned off. At least 5 hours are required for the fuel to cool down which stabilizes the EVAP pressure, thus making the EVAP system monitor more accurate.

The leak detection pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system, and malfunctions in both the canister pump module and purge VSV based on the EVAP pressure.

straight out of the repair manual

 

[SurferRob]

Theslammer21, thank you. Now I know.

 

[Jtraskell]

Ok, you guys who actually answered the question, you are cheating again.....reading the manual is not allowed on this forum!

 

[Theslammer21]

Ok, you guys who actually answered the question, you are cheating again.....reading the manual is not allowed on this forum!

****. my bad. forgot about that part. maybe a sticky is needed though?

anyone else think so?

 

[Jesse1983]

Ok, I added a "FAQ" section to the Mod/Writeup stickey. A thread to this can be found there. I still don't think it will eliminate these posts :redbrick: