Need advice on 2003 S500 default codes Pre-safe Inactive and Check Engine.


Asked by Apr 01, 2013 at 02:48 PM about the 2003 Mercedes-Benz S-Class S 500 4MATIC

Question type: Maintenance & Repair

Need advice on 2003 Mercedes S500 with default note stating "Pre-safe inactive and Check Engine light on. Problem is that the Transmission is not shifting from 2nd gear.  Note, I just tried detailing and washed the emgine compartment light.. Your help is sincerely appreciated.My e-mail addresses are: SAB3@Chrysler.Com and

5 Answers


pre sets ,or limp mode when a sensor disconnect ,failed or voltage blur like due to water in jack plugs of sensor . every thing returns after problem corrected.on a Benz I don't know if a scanner will be needed to erase code after dry out, or new sensor.or was a precondition existing? cant see a hood light having any effect even sumerged

2 of 2 people found this helpful.

Sorry, First of all my sincerest thanks for your advise. I will try to update this posting with my findings. I apologize for making a typo error on my question. I wrote " I washed the emgine compartment light" I actually meant, I washed the engine compartment last night. I left my S500 home and came to work in a loaner car. I hope you are right. I hope all that moisture from using the water hose will be dried off and my problem will be solved, by the time I get home tonight. My tel # is 248 760 7789, should anyone has any questions. Thank you sincerely. Syed.

1 of 1 people found this helpful.

I took my car this evening to Auto Zone. They check it out with the OBD2 sensor and told me: 1. Turbine speed sensor malfunction. This could be either due to poor electrical connection or due to a failed Turbine speed sensor. 2. Electrical transmission control system malfunction. This could be either due to poor electrical connection or Check powers and grounds to TCN. Although they Auto Zone sells several different sensors, they do not sell the Turbine Speed Sensor for S500. They strongly recommended me to take my car to a Mercedes dealer.


You have to get a used or new Electronic transmission module which is located in the right engine compartment fuse box attached to the fire wall.. Its a black box 5'' by 5''.. Thats your problem 100%….

3 of 3 people found this helpful.

Pre-safe inactive and check engine light is obviously caused by a faulty conductor Plate. I had the same problem with my 2002 S500 like 2 weeks ago, gone on Limp- Mode . I replace the conductor plate and the Fucken Asso is kicking and changing like never before.Do not be confused by anything else buddie.

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