Toyota Sienna 2012 - What is this part?


I have a squeaking sound that appears to be coming from this part. Can someone help me identify what this part is? Any help is greatly appreciated. Thanks in advance!

That appears to be the hydraulic control unit for the ABS.
Is the ABS warning light lit up?

That looks to be it! No, the ABS light is not on in the car. Is there any component in this that might squeal?

Is the noise constant? When does it make the noise?

The noise is mainly when turning on the car for the first time. It seems to go away after driving for a bit.

Did you just acquire this vehicle?
I ask because ABS-equipped vehicles go through an automatic ABS self-test when they are driven after being shut-off for many hours.

This varies considerably from one make or model to another, but on some models, that ABS self-test can be fairly noisy. Typically, the noise is heard after driving… maybe… 20 or 30 feet, and will not be heard again until the next “cold start”.


good guess from @VDCdriver, but I would suspect something more simple, like a worn serpentine belt in need of replacement


I agree, that part is near the belt drive area on the passenger side (it’s far away from the brake master cylinder).

We bought it about 6 months ago, but recently had to change the battery and alternator. Not sure if this could have reset something? I took it out today for a drive and the sound seems to come back every time I accelerate. It isn’t overly loud, but the sound is still there. Does that help?

It could be an idler for the belt that drives the alternator, or your new alternator could have noisy bearings. Did the noise start when you had the alternator replaced?

The ABS self test occurs at low speed just after starting to move forward for the first time. My 2005 Accord did it, it only first thing in the morning. I backed about 75 feet to the street, put it in drive, and by the time I hit about 10 mph, the test ran. I don’t notice it on my 2017 Accord or my wife’s 2019 Odyssey.

Then it isn’t the ABS self-test that you are hearing.
Both of the suggestions below are worth pursuing, as I think that they are the most likely.