Random error messages on board
11-15-2022, 04:37 PM
#1
Random error messages on board
Hi all,
I have a problem with my Class A, 2014. It happened few times now, when I am driving I start getting 'PRE-SAFE Functions limited' message. Then suddenly, I start getting all errors randomly : EPS inoperative, park assist inoperative, Active bonnet inoperative, Park Break inoperative etc...Also the car starts to suddenly act unresponsive, sensors start flashing, whenever I put turn signal (left or right) I should put them multiple times in order to function, switching from D to R becomes irresponsive also and I should do it multiple times to function....
If I turn my car off, it won't turn on again. If I leave it for a day or 2, it works again very normal ! Then suddenly the exact same happens again. I visited the garage which passed the obd tests and they got no fault codes!
For info, whenever I try to turn the car on the message 'Anti-theft protection activated' appears. And I get 'Risk of rolling error...'.
It seems that the car is displaying all the errors on screen randomly...
It also happens that when the car turns on no messages appear on the dashboard and the check engine light turns off.
Any idea what this could be? and how to approach this ?
Thanks!
I have a problem with my Class A, 2014. It happened few times now, when I am driving I start getting 'PRE-SAFE Functions limited' message. Then suddenly, I start getting all errors randomly : EPS inoperative, park assist inoperative, Active bonnet inoperative, Park Break inoperative etc...Also the car starts to suddenly act unresponsive, sensors start flashing, whenever I put turn signal (left or right) I should put them multiple times in order to function, switching from D to R becomes irresponsive also and I should do it multiple times to function....
If I turn my car off, it won't turn on again. If I leave it for a day or 2, it works again very normal ! Then suddenly the exact same happens again. I visited the garage which passed the obd tests and they got no fault codes!
For info, whenever I try to turn the car on the message 'Anti-theft protection activated' appears. And I get 'Risk of rolling error...'.
It seems that the car is displaying all the errors on screen randomly...
It also happens that when the car turns on no messages appear on the dashboard and the check engine light turns off.
Any idea what this could be? and how to approach this ?
Thanks!
11-16-2022, 11:34 AM
#2
MBWorld Fanatic!
Join Date: Apr 2019
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MY'14 W212 M276 3.5NA @60kMi
catch-22: silent faults....
You did a excellent job of describing this set of issues. The hard part is zero codes can be found: neither CURRENT nor STORED...
The fact turn-sigs and gear selector become extra slow, nearly irresponsive but functional at the same time makes me suspect the Steering Control Module SCM is in it for something. Its built-in angle sensor is used by ESP.
You can try to communicate with the module while the car is driven... I bet you will loose Coms and find it extremely hard to progress in these conditions.
Shared chassis goodness:
I am not exactly familiar with your A-class'14 chassis... yet I am pretty sure MB used some of its amazing standard technologies such as painted GND screws, solderless SCM module and the likes of distributed functions we come to appreciate.
GND posts:
Specifically pull back both sides of front footwell carpet to inspect/fix poor GND'ing screws. Do this while battery GND is disconnected, clean this one too! While under bonnet, charge up battery to full to see if proper voltage helps prevent this comprehensive chaos.
SCM:
You need to start poking around. Next we'll gently tap all around the steering column while car is not acting up to see if this can triggers a X-Mas tree display.
Voltage:
Find a way to display car voltage before/during event: how high/low is it?
Closer to 11v or 14v??
The fact turn-sigs and gear selector become extra slow, nearly irresponsive but functional at the same time makes me suspect the Steering Control Module SCM is in it for something. Its built-in angle sensor is used by ESP.
You can try to communicate with the module while the car is driven... I bet you will loose Coms and find it extremely hard to progress in these conditions.
Shared chassis goodness:
I am not exactly familiar with your A-class'14 chassis... yet I am pretty sure MB used some of its amazing standard technologies such as painted GND screws, solderless SCM module and the likes of distributed functions we come to appreciate.
GND posts:
Specifically pull back both sides of front footwell carpet to inspect/fix poor GND'ing screws. Do this while battery GND is disconnected, clean this one too! While under bonnet, charge up battery to full to see if proper voltage helps prevent this comprehensive chaos.
SCM:
You need to start poking around. Next we'll gently tap all around the steering column while car is not acting up to see if this can triggers a X-Mas tree display.
Voltage:
Find a way to display car voltage before/during event: how high/low is it?
Closer to 11v or 14v??
Last edited by CaliBenzDriver; 11-16-2022 at 11:42 AM.
