One problem related to power assist brake has been reported for the 2004 Mercedes Benz E320. The most recently reported issues are listed below.
Brake failure, caused a major collision. Car did not stop in time to avoid another vehicle. Also electrical issue. Consumer received a letter stating that his vehicle was included in the recall. Recall stating that the pump motor may run out of permissible tolerances thereby triggering they hydraulic backup function mode leaving consumer to use greater brake pressure leaving brake travel longer likely to result in an accident.