Chay

2002 4Runner SR5 4x4 3.4L ~200,000km

So˟I˟encountered a strange Buzzing noise coming from the Throttle Body yesterday; Key on / Engine off.˟

I’m not sure if I should be concerned, but I am paranoid because we are soon hitting the Hwy for a weeks’ worth of holiday travel through the mountains in the summer heat.˟

Yesterday˟I˟was changing the 3 belts on my wife’s DD & checking over a few bits & such.˟I˟turned the Key on & left it on to check something; the ABS motor cycled a few times like it does & then cut out.˟˟Then˟I˟was able to hear a faint buzzing, accompanied by a faint high pitched whine.˟˟I˟snooped around traced it to the throttle body.˟˟When I gave the throttle cable pulley a twist to open it, the faint noise instantly got louder & would not go away (almost like toast stuck in the toaster).˟˟I˟then turned the key off waited a few seconds, then back on again & the same faint buzzing came back, followed by the louder buzzing when I fiddled with the butterfly.˟˟I˟tried this a few more times and only got as far as the head scratching phase of the diagnosis.

I searched around here &˟TR4.org˟˟for˟solutions˟today˟but had very limited success.˟˟One of the threads mentioned a buzzing coming from the TB, but did not elaborate on it; another mentioned an “Accelerator Pedal Position Sensor” that may have problems (I’ve never heard of one of those before).˟

I’m assuming the sensor on the fire wall side with the 4 wires from it is the TPS.˟˟But what is the item on the front side (by the throttle cable pulley) with the 2 wires coming out of it?˟˟Is that an “Accelerator Pedal Position Sensor”?

A few notes:

It only took opening the TB a fraction of the way and the noise got loud.

I˟couldn’t hear it with the engine running (but that could have been because the engine was running)

There are no CELs coming up nor˟is there any noticeable operational issues.

We’ve had this truck for 8 years (125,000km) and˟I˟have never heard this noise coming out of it before now, (so it’s not just something I’ve never noticed)

Has anyone seen anything like this before or can anyone point˟me˟in the right direction?

Is this an actual issue, or am˟I˟just being paranoid?

Any assistance or inspiration would be great, thanks

Chris

Chay

Anyone... Bueller ??

TheDurk

Your year has throttle-by-wire ('01-'02 only). I'm not familiar with it as I have a '99, but I suspect your issue is in that system. Recognize your throttle cable is just a 'limp home' back-up if the throttle motor fails. It won't even open the butterfly all the way. Also recognize that posts relating to other years than '01-'02 won't apply to your motor. That's all I can tell you, but I didn't want you to have no response at all.

Chay

Thanks, Durk, it adds an extra clue to the mystery that I didn't have before.

Chay

So I've been Googling around, and details are very slim on the Throttle Motor Actuator for the 01-02 3.4L. Does anyone know if this is integrated into the TPS or is it a separate unit? is it replaceable by itself, or is it part of a larger component(s) that all have to be bought from Toyota directly for an absurd amount?

Any insight or thoughts are welcomed.
Thanks,
Chris

Chay

So a year has gone by and the only things I've come up with are that this may also be called the throttle position motor actuator and that replacing the throttle body may solve the issue. That's a $918 maybe. There is supposedly a magnetic clutch in there somewhere too.??

There has not been any driveability issues except for a similar loud electronic sounding chattering noise coming from under the hood under between 60-85Km/h, regardless of load or RPM or which gear it's in. According to my wife, it is more noticeable through a wider speed range while I'm driving. Guess I have heavier feet? It doesn't seem to do it while in park while I'm increasing Rpm manually, by opening the TBody by hand.

Anyone have any suggestions ?
Thanks
Chris

johnkl

Hi, I came across your post searching for a solution to the same problem. now 3 or 4 years later and there is still little to no information on this issue. Did you ever resolve the problem? My symptom is; I shut the ignition off the I hear the sound is that of a small motor running, I traced it to the throttle position motor, if I unplug the throttle position sensor it will stop but otherwise it will run for about 20 seconds before stopping. As you stated it doesn't effect operation but this can't be good.

75w90mantraN

https://forums.nasioc.com/forums/sho....php?t=2252137
Although its talks about other makes, the function is the same. Some have commented that its normal and cleaning the TB doesn't do anything (though it's good to do). Others fear the noise. My thoughts - if there's no associated codes and issues with driving, its fine.
I think I get that noise too. It may be just electrical in nature. Like the engine wants you to turn it on so it can take you for a spin.