Pre safe limited
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Joined: Aug 2003
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From: NY
2014 E550 4matic,, sold 2012 E 350 4matic,,sold 2010 e350 4w,sold 2002 e320 se
Pre safe limited
Any ideas on why this message would suddenly appear when nothing abnormal occurred to the vehicle?
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
Would you mind posting the exact message?
Have you checked under the front seats that there are no loose connections?
If not, start by reading @CaliBenzDriver https://mbworld.org/forums/e-class-w...ml#post8451931
Have you checked under the front seats that there are no loose connections?
If not, start by reading @CaliBenzDriver https://mbworld.org/forums/e-class-w...ml#post8451931
Last edited by JCM_MB; Dec 6, 2022 at 02:05 PM.
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
👍
Would you mind posting the exact message?
Have you checked under the front seats that there are no loose connections?
If not, start by reading @CaliBenzDriver https://mbworld.org/forums/e-class-w...ml#post8451931
Have you checked under the front seats that there are no loose connections?
If not, start by reading @CaliBenzDriver https://mbworld.org/forums/e-class-w...ml#post8451931
For people pressed for time, the shortcuts are- Either scan your car for specific clues
- Or book a appointment with a specialist
Pre-Safe messages are a catch-all with multiple distinc causes. Analog radar modules don't fare well in unstable environments.
Thread Starter
MBWorld Fanatic!
Joined: Aug 2003
Posts: 1,138
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From: NY
2014 E550 4matic,, sold 2012 E 350 4matic,,sold 2010 e350 4w,sold 2002 e320 se
It said presafe functions limited refer to owners manual...Today it disappeared,,had to be dirt or something in or around a sensor...2 days ago I parked in a driveway very close to a building wall,,never touching it...after I left that location the msg appears...we had rain since then,,,today I saw no msg,,in fact the display had no prior msgs to show me....dayum.
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Joined: Jan 2019
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2015 E350 4Matic Wagon, 2018 GLE350 4Matic
For what it's worth, I've had similar messages on my two MBs that turned out to be low main battery charge. One had a 5+ year old main battery and the other had only been driven short distances. If your battery is original it might be your first sign it's time to replace it.
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2020 GLS450 (wife) / 2024 Ford Bronco (mine) / 2014 VW Tiquan (son)
Its a PIA (pain in the ****) system. Mines been doing for a long time. Sometimes insistent sometimes not for months. Thought it was the drivers seatbelt latch. So i replaced it. Didn’t come back for about 3 weeks, than bam, its back. It does not store codes either. To figure it out, it basically has to happen when a good scanner is already attached and showing real time voltage to spot where the issue is. Every time its on for ky car and I point the thing towards my mechanic’s shop who takes of my car, it turns off and won’t come back on….
you can try this though - buy a can of electric cleaner from one of the car stores, and spray down into your seat belt latch. If it shuts it off for a while; then you’re on the right path, but it might be more than just one spot around the car too.
it does not impact the driveability of the car though…
you can try this though - buy a can of electric cleaner from one of the car stores, and spray down into your seat belt latch. If it shuts it off for a while; then you’re on the right path, but it might be more than just one spot around the car too.
it does not impact the driveability of the car though…
Thread Starter
MBWorld Fanatic!
Joined: Aug 2003
Posts: 1,138
Likes: 7
From: NY
2014 E550 4matic,, sold 2012 E 350 4matic,,sold 2010 e350 4w,sold 2002 e320 se
Many thanks on all the thoughtful possibilities,,,these cars are sumthin else,,,It should be noted I don't drive the car much anymore since I fully retired at the beginning of the China virus,,(3/2020)..but I did change the original battery out 2 yrs ago..did it myself and all was going just fine when I was putting 250 miles a week on the car,,,now I barely put 40 miles a month...it has 54k original on it.. I was told by many top Benz techs,,,these things need to be driven,,I fear I may be unknowingly hurting the car.
Truthfully though,,this is the finest most capable car I've ever owned including my first 3 Benzs...I couldn't resist owning the last V8 E that wasnt AMG..maybe ill just drive it more
Truthfully though,,this is the finest most capable car I've ever owned including my first 3 Benzs...I couldn't resist owning the last V8 E that wasnt AMG..maybe ill just drive it more
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Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Shortcuts for JOY...
In a perfect world owning these great cars should be an awesome experience. Unfortunately the electrical system has a learning curve.
> The main battery gets drained more or less rapidly and only get charged properly on occasions. Owning these vehicles requires help with the chaos engineered in each system.
> Modern keyless cars only sleep with one eye keeping the minimum electronic awake to listen for a nearby key handshake.
When a near match is found the F-SAM powers up further circuits to validate the driver's keyfob.
> Some switches use dry-contact relays, some are Solid States Relays with inherent leak through current (same thing that discharges LED flashlight battery when unused).
> Not all modules are able to sleep well with buggy 3rd party firmware. More often than not SAM power managers stay awake to babysit CAN modules gone wild. Normally CAN buses go quietly to sleep but CAN-B soft-crashed modules entire strings of modules are kept awake processing noise. Same thing with LED headlight modules, goofy blowers...
😏
> The basic shortcut is to float charge AGM battery and reboot the car about once a month to clear sleepless modules.
DO NOT rely on the 300Amp alternator to charge a drained battery, this overwhelms the pre-fuse path with unlimited current: fried battery!
Get a great charger such as CTEK, it will pay for itself.
> The main battery gets drained more or less rapidly and only get charged properly on occasions. Owning these vehicles requires help with the chaos engineered in each system.
> Modern keyless cars only sleep with one eye keeping the minimum electronic awake to listen for a nearby key handshake.
When a near match is found the F-SAM powers up further circuits to validate the driver's keyfob.
> Some switches use dry-contact relays, some are Solid States Relays with inherent leak through current (same thing that discharges LED flashlight battery when unused).
> Not all modules are able to sleep well with buggy 3rd party firmware. More often than not SAM power managers stay awake to babysit CAN modules gone wild. Normally CAN buses go quietly to sleep but CAN-B soft-crashed modules entire strings of modules are kept awake processing noise. Same thing with LED headlight modules, goofy blowers...
😏
> The basic shortcut is to float charge AGM battery and reboot the car about once a month to clear sleepless modules.
DO NOT rely on the 300Amp alternator to charge a drained battery, this overwhelms the pre-fuse path with unlimited current: fried battery!
Get a great charger such as CTEK, it will pay for itself.
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