Truck is making an intermittent strange noise

Tiny
NOTRICH
  • MEMBER
  • 2006 TOYOTA TUNDRA
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 216,000 MILES
My truck is making an intermittent strange noise that sounds similar to a starter that is failing to engage (2-3 second whining noise). It only makes this noise while slowing to a stop. Just before the complete stop, I can feel the brake pedal drop 1/4 inch or so. My mechanic has been no help so far because, as we all know, it fails to occur while the mechanic is driving. He says it is probably not brake related but, because of the extra pedal movement just before stopping, I tend to disagree. He also says it may be the starter, but why would it make the noise only during stops? Any ideas guys?
Friday, May 21st, 2021 AT 9:23 PM

12 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

Based on your description, it sounds like the ABS is engaging. If there is a faulty wheel speed sensor, it will cause the system to think one of the wheels is locking up.

Do me a favor. Take a look through this link and let me know if it is something you are comfortable trying. You will need to test each wheel.

https://www.2carpros.com/articles/abs-wheel-speed-sensor-test

Let me know if you can perform the test. I have a feeling what you hear is the ABS.

Let me know.

Take care,
Joe
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Saturday, May 22nd, 2021 AT 8:59 PM
Tiny
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Hi Joe,

Thanks for the quick reply. I have read the article and watched the video. This is definitely something that I will check out. I am at my wits end trying to determine what the problem is. But I have another question. If the ABS sensor is bad, shouldn't the ABS light on the dash be on? Thanks.
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Saturday, May 22nd, 2021 AT 10:34 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

That's a good question. The answer is no. If the sensor is producing any signal, the computer won't know if it is correct or not. Thus, no light turns on. If the sensor is cut and there is an open circuit, then yes, it should turn on.

Let me know what you find or if you have other questions.

Take care,

Joe
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Sunday, May 23rd, 2021 AT 7:01 PM
Tiny
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Thanks so much for your help. I'm very busy right now, so it may be a while before I get around to checking on it. I have been driving it this way for several months because my mechanic said not to worry. If you think it is dangerous to drive, please get back to me ASAP. Otherwise I will get back to you after I have a chance to check it out. Thanks again.
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Sunday, May 23rd, 2021 AT 7:21 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,068 POSTS
Hi,

You are very welcome. I have to be honest, without knowing for sure if this is the issue, I'm not sure if it is a concern. If the tech who checked it said it isn't, you should be fine.

You know, I had another quick test for you to try. If you remove the ABS fuses from the vehicle, it will turn off the ABS. You will still have standard (non-abs) brakes. That would tell us if what you hear is coming from the ABS.

I thought it would be easy to identify the fuse, but as expected, it isn't. LOL I need to know if you have a crew cab, if the vehicle has stability control, if it is a regular cab, and so on. The fuses are all in different locations based on the vehicle.

If you look at the attached pic below, it identifies the options. If you want to try this, let me know which one you have and I'll be able to look up the correct information.

Take care,

Joe

See pic below.
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Sunday, May 23rd, 2021 AT 7:32 PM
Tiny
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This is a 2006 Toyota Tundra Crew Cab SR5, 4.7L engine, 2WD, disk brakes on front, drum brakes on rear, no stability control.
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Sunday, May 23rd, 2021 AT 9:00 PM
Tiny
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Well, I got the owner's manual out tonight to try to find the ABS fuse(s) and lo and behold, the fuse box diagram does not match what is actually under the hood. So I went to 3 different websites to try and track down the info and guess what? All three websites referenced different fuse numbers to control ABS. So at this point, I am very confused where to go next. One site even stated the ABS fuse also controlled the multiport fuel injection system. If that is correct? That does away the theory of driving with the ABS fuse uninstalled to run the test.
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Monday, May 24th, 2021 AT 7:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

I found it, but it is a fusible link and not a traditional fuse. It is in the fusible link box under the hood. It won't be something that can easily be removed.

I attached the wiring schematic for this vehicle's ABS system. I highlighted the power supplies to the ABS and added the pics of the fusible link.

I have to be honest. It would likely be easier to disconnect the ABS actuator to see what happens. It will set the ABS light on until it's reconnected.

The actuator is under the hood on the passenger side of the vehicle. There is a cover over it. You will need to remove the cover to access it.

If you look at pic 4, it shows the location of the actuator. Pic 5 shows the actuator and the connector. There is a slide that you move upward and then the connector will come off.

If you still want to try this, you can pick which you feel more comfortable doing.

Let me know what you find.

Take care,

Joe
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Monday, May 24th, 2021 AT 7:49 PM
Tiny
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Thanks Joe for taking an interest in helping me on this. I will get back on this as time allows and will follow back up with you then.
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Monday, May 24th, 2021 AT 9:28 PM
Tiny
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You are very welcome. I look forward to hearing what you find.

Take care,

Joe
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Tuesday, May 25th, 2021 AT 7:56 PM
Tiny
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  • 7 POSTS
Joe,

Is this the ABS actuator that you advised me as the best way to temporarily disconnect the ABS? Since it has five lines leading to the master cylinder and I assume each brake, I believe this is it. It has an unusual electrical connector that looks like it may be difficult to disconnect.
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Wednesday, May 26th, 2021 AT 8:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

That's it. As far as the connector, pull up on the slide. That will release the lock and then you will be able to remove the connector.

I attached a pic below showing the lock slide.

Let me know.

Joe
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Wednesday, May 26th, 2021 AT 8:53 PM

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