Pre-Safe inoperable, esc off & loss of throttle
I've seen similar posts where it was suggested that it could be the pedal or aux battery. I changed main battery last year and aux battery about 2-3 years ago.
Was going to get it scanned for codes but dreading driving the car as it's happened about 5 times in about an hour. Most likely have to tow. Guess I'll have to invest in an diagnostic tool.
Any thoughts as to source of problem?




I'll side with post #61 that points at front RADAR Modules as the source of Pre-Safe errors. I became familiar with this on my MY'14 that matches OP's year.
The seatbelt pre-tensioners could be prime suspect for these errors if Distronic was not also pointed out... best way to find out is to scan the car for clues.
I've seen similar posts where it was suggested that it could be the pedal or aux battery. I changed main battery last year and aux battery about 2-3 years ago.
Was going to get it scanned for codes but dreading driving the car as it's happened about 5 times in about an hour. Most likely have to tow. Guess I'll have to invest in an diagnostic tool.
Any thoughts as to source of problem?
++++ TSB DTC# C10C700 : "Collision Prevention Assist Functions are Restricted"
>>> Here is the public link to this fix
Mercedes-Benz TSB LI30.30-P-059421 reads:
"...The control unit 'COLLISION PREVENTION ASSIST' has a malfunction because the radar sensor is maladjusted...."🙂
Last edited by CaliBenzDriver; Sep 27, 2021 at 09:58 PM. Reason: LI30.30-P-059421
Disable that stupid pre-safe nanny control crap-not the contributor to power loss
ESC is gonna be an ABS sensor or related because you just fcked one of them up while you did the brakes-the contributor to power loss




I have iCarsoft II scanner that is one of the lower cost ones, but there are other better scanners I believe at around the same or slightly higher price.
My scanner said the front left wheel speed sensor is bad in several modules and replacing that sensor fixed it all. I started the thread "Christmas tree lit up" for it.
Easy job, sensor was around $150 from the dealer if I recall correctly. I would not use third party part for this one.
P.S. Forgot to mention this happened with my S550, but I think it is built the same way as E-Class for this part.
Last edited by Arrie; Sep 27, 2021 at 05:13 PM.
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Can anyone make sense of these codes?
codes.Do I need to replace the pedal? 24hrs after my first post, the moment I touch the accelerator pedal the warning lights come on.
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Multiple items failing at the same time would be a massive coincidence so it did not happen. Something that is common for these items/issues is what failed and is causing error codes for them all.
But, for the heck of it, read what each speed sensor reads when driving... also you could read what the gas pedal sends out when you press it. Should not need to drive for this.
Multiple items failing at the same time would be a massive coincidence so it did not happen. Something that is common for these items/issues is what failed and is causing error codes for them all.
But, for the heck of it, read what each speed sensor reads when driving... also you could read what the gas pedal sends out when you press it. Should not need to drive for this.




- CHARGE batteries
- disconnect battery 5mn to reset car
- Clear all DTC with scanner
- Test drive less than 20mn
Last edited by CaliBenzDriver; Sep 28, 2021 at 02:38 AM.




- CHARGE batteries
- disconnect battery 5mn to reset car
- Clear all DTC with scanner
- Test drive less than 20mn




FCP Euro
Mercedespartscenter.com
Might be more economical than the dealer, Try reset first, and as Calibenz says, check and clean plug and harness connections/ reset sequence before replacing parts?




This is really a scanner limitation (bug), not the car network being stubborn.
TROUBLESHOOTING 101:
I totally subscribe 100% to "go with the obvious first" when possible. Here we have a spread of faults pointing to a glitch.
Sometimes you get lucky and sometimes you replace parts then wonder why it doesn't work... It's better to troubleshoot up front.
Poke around before ordering an APP that may require SCN.

Last edited by CaliBenzDriver; Sep 28, 2021 at 04:35 PM.
Changed the pedal, no change. Message still pops up. Checked the ground points I worked near, found one was corroded. Cleaned but still getting the DTC. Checked all fuses and none are fried. Trying a reset by disconnecting the battery. Hoping for the best.




I'll keep this short:
Ensuring you have good starting and running voltages available will help a long way but it's not the cure.
Indulging in "Charge and Resets" can get you effective but temporary relief from goofy ECU/SAMs.
Consider fixing the bad GROUNDS points from front to back.
I'll keep this short:
Ensuring you have good starting and running voltages available will help a long way but it's not the cure.
Indulging in "Charge and Resets" can get you effective but temporary relief from goofy ECU/SAMs.
Consider fixing the bad GROUNDS points from front to back.




Recently I had a look at the APP diagram. It's a dual independent circuit, not directly grounded. One circuit goes up while the other one goes down, very much like the throttle body control circuit. When APP opposite signals are found to be mismatched, ECU pulls a limp-mode to prevent uncontrolled rpm.
PreSafe, Pedal, EVAP.... all these faults are not individually significant here. I wish I could simply help you with a TSB repair or one specific ground screw... but this is spread out issue.
All (ECU) grounds need to be equally good. ECU uses half dozen or more GND between engine screws and body posts.
Different GND points affect different ECU circuits. Instead of trying to figure which is what without an internal ECU schematic... I went for an ALL Inclusive quest.
There are 2x published GND's in driver footwell... I am still missing the 2nd one that may require my driver seat to fly out...
I used to get your exact set of errors (PreSafe, APP...) I have not had it in the past 25kMi.
🤞
Last edited by CaliBenzDriver; Oct 2, 2021 at 08:45 PM.




If by any chance the next one you clean fixes the problem, will you stop cleaning them immediately and move on? Or clean as many as possible?
obviously recent. Grease all over the inside of the wheel. I'm assuming that maybe the sensor is noticing something. The axle boot is intact and all the control arms are new. Could it be leaking out of the edge of the axle boot or is this from the bearing?




obviously recent. Grease all over the inside of the wheel. I'm assuming that maybe the sensor is noticing something. The axle boot is intact and all the control arms are new. Could it be leaking out of the edge of the axle boot or is this from the bearing?
and what's the fix to this. New axle?
Last edited by N7legion; Oct 2, 2021 at 04:57 PM.




Whomever replaced your new lower arms cause that weakness to surface.
Axle is now low on grease while your caliper and inner brake pads are coated.

greased up brake parts
Wipe excess grease and spray brake cleaner to finish degreasing all this mess
Last edited by CaliBenzDriver; Oct 2, 2021 at 05:14 PM.


