02 S80 T6 , Brake Assist Service Required

Jah-Sun · Post by **Jah-Sun** » 13 Jan 2013, 22:29

Recently I have lost the use of my cruise control, I am now getting the message "Brake Assist Service Required".I read that the message and the loss of cruise control are related. I am getting several codes when put under the scanner, P0573, P0422 and P0432. P0573 being the code related to the cruise control issue.
Is this something I can repair myself or do i need to get an expert?

Post by **regent** » 14 Jan 2013, 08:25

P0573 = Brake Switch
P0422, 0432 = CAT CONVERTER EFFICIENCY (Possible causes: Uneven compression, Air leakage in the intake system, Air leakage in the exhaust system, Faulty fuel pressure, Defective three-way cat.
I would start checking for vacuum leaks. After finding and fixing those, clear the codes, and see if they reappear.

Vacccum leaks may adversely affect the vacuum brake booster efficiency and cause cat to be seemingly bad. Brake switch may be an unrelated fault.

In many situations Cruise CTRL may be inhibited because of an intermittent or a persistent fault.