ABS Noise Only When Stopped. Help?

I've enjoyed this forum for years and found the community VERY helpful. This is my first Tacoma issue I have yet to resolve either thru this site or outright on the web. Hence, my 1st post. Otherwise, my Tacoma has performed flawlessly for 180,000+ miles.
Background: Tacoma PreRunner, 2011, V-6. I am the only owner. No modifications.
Issue: When I stop at a stop light, or for a short period of time, with my foot on the brake, a metallic chatter bangs rapidly and loudly from under the hood. This occurs about 40% of the time. But it never happens at a dealership or a place with a diagnostic tool - of course.
This is what I do know:
- The noise occurs more frequently as the vehicle operates - say, 10-miles or more.
- No ABS warning light lit
- No Brake warning light lit.
- No trouble stopping.
- No noise when parked with the engine running.
- If I put the transmission in Park there is no noise.
Work Around:
- I leave the vehicle in Drive at a light, depress the emergency brake 2-clicks, and let up when the light turns green.

This is fine with me, but my wife will no longer drive it. I've driven it in this manner for more than 5k miles. . . .

Has anyone experienced a noise from under the hood only when the engine is running, at a stand still, with the foot brake applied? I open to any thoughts. . . .

 

First pop the hood, then have the wife get behind the wheel and go through the motions in the driveway or a parking lot until the noise starts and then you look ?

 

If you’re not sure it’s the ABS pump, disconnect the power supply to the pump motor and see if it stops.

 

I have never had the opportunity to pull off the road or duplicate in the driveway, and troubleshoot as suggested. It seems to 'know.'
Boy, how I have tried and will continue to try. When I stop for fast food the noise can be deafening when reflected from the building. . . .or perfectly quiet. That's what's made troubleshooting at a dealership so impossible.
. . .also, other passengers have heard it as well, so I haven't lost my mind yet. . . .

 

I see the plug at the pump. Can I still drive it with the plug unplugged?

 

. . .reasonably safely I mean?

 

Yes , you just won’t have ABS , regular hydraulic braking ability should remain

 

I had a rusty wheel speed sensor on a Camry cause this a while back , it was giving bad info to the abs system

 

I'll try stopping in the backyard 1st before taking it on the road. That "should" word always gives me 'pause.' Thanks for the followup.

 

. . .when your vehicle was stopped. . . ?

 

When slowly rolling and coming to a complete stop as the pedal reached the lower end of travel it would trigger the abs pump because it was not reading the abs ring on the axle , just saying it’s worth a look if unplugging the pump eliminates your noise

 

I went ahead and followed your advice. I have unplugged the pump and took it on a 12-mile loop. The ABS, Brake and Traction control warning lights are ON but the vehicle stops straight and true without the ABS (as it should with a proper brake job). Even crash stops stay even without pulling. Tomorrow I'll take it shopping and give it a real road test.
. . .but there are NO sounds emanating as the vehicle slows or rolls at all. Only when stopped with the brake ON (but no noises during this tested). Should tomorrow's test prove successful (no noise when stopped) I will probably conclude that there is a failing 'something' within the ABS pump and replace it. Thank you for your counsel.

I'm ruling out a wheel sensor at this time because the wheels are stationary when the noise occurs.

 

this is a 3rd gen thread

 

If a third generation thread would be useful, would you be so kind as to point me in the right direction???

Did that. Disconnect the ABS pump assembly. All alarm warning lights on and no speedo. Drove 42 miles with it disconnected and the sounds returned on two occasions - and only when stopped with the brake applied. Back to square one. Drove around with my wife and when we heard the sound, I pulled off the road and she jumped out and I popped the hood. I swear the truck knows when we're troubleshooting because the noise could not be repeated on the side of the roadway.

CONSIDER: If the ABS pump is unplugged and the brakes are applied, I 'think' the normal brake pressure could/might affect a failing ABS piston thing? I really hate throwing money at anything without understanding what or why I'm making a purchase.

 

uhmm. maybe a 2nd gen thread

 

I believe what @RIX TUX is trying to say is that you posted this inquiry in the 3rd generation section (2016-2023), where people may not be intimately familiar with your 2nd generation truck (2011). It might behoove you to post this in the respective section where you might get better advice by someone who has had your problem with their own truck.

 

Got it, thanks.
Done here.