Brake pulsing in park, drive etc?????/

[dutch]

When either my car is in park or if im in drive etc with the brake pressed, I get a pulsating in my peddle. But it doesnt happen when the car is in motion or when im stopping.

This jus started within the last day or so.

Anyone had this before?

[sunrunner_pei]

Nope, that's a new one for me. :( I would guess something with the brake booster or vacuum lines, but that's only a guess. Anyone else?

[rixGAphx]

Originally posted by sunrunner_pei
Nope, that's a new one for me. :( I would guess something with the brake booster or vacuum lines, but that's only a guess. Anyone else?
Never heard of it before, but the lines to brake booster are my initial guess also.
Maybe the check valve.

[Colin]

Yeah , never heard of that when stopped . Just a guess but , ABS acting up . Or something with the booster unit ? :???:

[HeyDace]

Your EBCM is running self test. This should happen only once at start-up. The probability is either a bad connection at the EBCM power or ground circuit or a bad speed sensor circuit or sensor or a bad motor pack. You will need to have the ABS scanned for any codes.

[dutch]

Good info, but is scanning the ABS codes done the same way as I'd scan for any other codes?

[rixGAphx]

Originally posted by dutch
Good info, but is scanning the ABS codes done the same way as I'd scan for any other codes?
No.

The main engine 'puter (the PCM) is OBD II, and is scanned with a conventional OBD II tool that references standard and GM-specific engine/tranny codes.

The ABS 'puter is different, and has its own connector and GM-specific codes.
GM dealers and *many* larger brake shops have the scan equipment and codes.

-Rick