PSE system/voice control/Tele Aid module failure may cause lack of audio/dead battery on Mercedes-Benz E420

PSE system, voice control module, or Tele Aid module failure can cause a lack of audio. These same modules can also cause dead battery conditions when they fail to "time out." Many electronic control modules are active even when the engine is off. If these modules stay active, they will drain the battery, which is why they have a timer built into the modules. The timer shuts down the modules after a preset amount of time (timing out). If a module does not time out, it will stay active and drain the battery.