benz_addict

Just bought a 2004 S500 LWB 4Matic:

1 Malfunction - Pre-Safe Inactive

Car has 43,000 miles, everything else works fine. Not sure when this message came up but the car is at the dealer right now and will be delivered to my house sometime this week.

What does the message indicate? Does the ECU need a reset?

my06clk

That usually happens when you take the steering wheel off with the ignition turned on.. it will go away after you drive about 30 to 45 minutes... "normally"

brakel8

Pre safe inactive will be displayed after a low voltage or battery disconnect. If there are no faults with the vehicle all that needs to be done is re-synchronize the passenger seat, steering column, windows, sunroof and initialize the steering angle sensor.

whoover

If Pre-Safe senses a possible accident (very hard braking or braking while swerving usually) it cinches up the seatbelts, moves the seat to the optimal crash position and closes the sunroof -- all in milliseconds. I've managed to trigger the system a couple of times and it works very well. It's quite a thrill to have your seatbelts confirm that your passing maneuver was world-class. They make a kind of Robocop sound as they cinch up and then relax again as soon as they realize all's clear.

One of the sensors or control modules in the system has failed or needs calibration. It could be brake electonics, stability control or a Pre-Safe module. You want it working. It's one of those systems that makes an S-Class an S-Class.

benz_addict

ok cool thanks for the replies guys

picking up my S500 tomorrow morning my previous car was a 06 w203 c230... BIG difference

m3j0n

how do you do this resynchronization?

STRGLZ

I just want to say that Pre-Safe can also be caused by a faulty ABS sensor. I got one on mine and it causes this message to appear. However, it usually appears with other malfunctions such as ABS, BAS and ESP, so if you only got the "Pre-Safe Inactive" and no other malfunction, it's unlikely to be the cause.

For the windows : hold down the button until the window is completely down, then pull it up and hold for approximately one second. Do this for all 4 windows. When they need synchronization, windows won't pull up or down automatically.

For the sunroof : this one is a bit tricky at first, but once you get it it's easy. First you gotta open the sunroof completely by holding the button, then if I'm correct you hold the button up just like when you open it in popping position. I'm not sure if I'm right, I remember it was quite tricky when I had to do it. Anyway what you need to do is open and close the roof all the way, so find find what works works and hold it for a few second. If you can open the sunroof automatically, it worked. When it needs to be resynchronized, the sunroof acts weirdly when you press the button in any direction. For example, pressing up can open the sunroof instead of popping it.

For the steering angle : start the car, turn the steering wheel all the way left, then all the way right. Do this 3-4 times, then restart the car. When it needs a synchronization, you usually have "ESP Visit Workshop" and "Pre-Safe Inactive" that show on the dash.

If you don't have any of these symptoms, you don't need to synchronize these.