ABS self test

[Bayarea Q]

911,

Thanks for you post! I think you were right about the noise/feel I was describing in my brake pedal when I back up. I tried during my lunch brake and it would only do "it" the first time I tried.This is the first I ever heard of a ABS self test. I'm very relieved to hear about it!! If someone knows or can exlpain the process I would appreciate it.

[Q451990]

Honestly, I'm not sure how the self test works! I checked the service manual, but didn't find an explanation. I would think the pump tries a few pulses and then the speed sensors check to see that the wheels slowed slightly. That would confirm that the pump and sensors are working...

The test can be very disconcerting if you don't know what it is! I've had several passengers think I ran over something when it happens. I always notice it more when backing downhill too.

Heath

[911/Q45]

Glad I could help, unfamiliar weird noises are bad!