17-NA-314

Intermittent Service Power Brake Assist Message With a Brake Shudder and Possible DTC P0557 Set/Stored Condition Customer may comment of an intermittent "Service Power Brake Assist" message which may be accompanied by a brake shudder. During diagnosis a technician may find DTC P0557 set or stored. Cause This condition may be caused by the Power Brake Booster Vacuum Sensor providing intermittent incorrect vacuum values due to circuit board fault. Correction Replace Power Brake Booster Vacuum Sensor & Hose Assembly.