Pre safety features not working. Dashboard warning

[Carol]

I returned from hols , 2000miles 3 weeks ago , then went out to start my van and would not turn , put battery on charge using points under bonnet , after 2 days all started and running , but l get pre safety features not working, Has anyone else experienced this

 

[j200george]

Yes. It was an abs sensor fault on one wheel. Cost about £160 to fix at an independent. Common fault loads have had it.

 

[Carol]

Thanks for that , l will get it checked , noticed seat belt tensioners not working , so will check fuses ,
My next service will be at MB specialist non franchise family business, so sure they will sort at reasonable price

 

[j200george]

Thanks for that , l will get it checked , noticed seat belt tensioners not working , so will check fuses ,
My next service will be at MB specialist non franchise family business, so sure they will sort at reasonable price

Mine was intermittent. The alert came on and sometimes go off. Next day the car started a journey with no alert then perhaps come on after 5 mins of driving.

If you have access to a diagnostic monitor of some sort it’ll be apparent. Not a big issue they do age over time and degrade.

 

[Carol]

The seat belt tensioners are the ones that tighten a little when ignition is put on .

 

[j200george]

The seat belt tensioners are the ones that tighten a little when ignition is put on .

I have never noticed this at all. What model year is your MP? In my limited experience such tensioners pre fire in advance of a collision only. This to limit any force impact on your torso.

The Mercedes pre safety functions are in the 2019 Mp outlined below (probably no exhaustive) but if various conditions are not met then you get the pre safe functions limited. It could be another issue you are experiencing but we have had a few of these posts recently and it was an abs wheel sensor that was the root of it.

• Detects critical driving situations (for example an imminent collision) using sensors and warning systems.
• Automatically initiates precautionary occupant protection measures, such as tightening front seat belts (pre-tensioners) to restrain occupants more firmly.
• Possibly closes windows / sunroof or moves parts to reduce injury risk (if fitted). While I didn’t find in every spec sheet that this is guaranteed, this kind of action is standard in many Mercedes PRE-SAFE systems.

Feature	What it does	Whether it’s standard / optional in 2019 Marco Polo
Collision Prevention Assist	Warns the driver if a collision risk is detected ahead, gives warnings; may assist braking.	Optional, often part of “Driving Assistance†package.Â
Adaptive Brake Assist / BAS PRO	A more advanced brake assist that can increase braking if driver reacts late, etc.	Optional.
Active Distance Assist (DISTRONIC)	Keeps a safe distance from vehicle ahead (adaptive cruise function) in traffic or highway.	Optional on many trims; part of driver assistance packages.
Lane Keeping Assist	Warns if drifting out of lane / helps prevent unintended lane departure.	Optional. Possibly standard on higher-spec / with certain packages.
Blind Spot Assist	Alerts driver to vehicles in blind spots when changing lanes.	Optional.
ATTENTION ASSIST	Monitors driver behaviour (via steering, etc.) for signs of fatigue or reduced attention; gives warning.	Standard or frequently included.
Crosswind Assist	Helps with vehicle stability during strong side winds.	Standard in many markets for Marco Polo.
Highbeam / Headlamp Assist	Automatically adjust headlamps (dipping / bright) to avoid dazzling others.

These are the other features in the 2019 Marco Polo which are relevant, and which PRE-SAFE is integrated with (or complements). Some are standard, some optional, depending on the variant / package you have.

 

[Carol]

Thank you , never seen this list before ,l believe l originally set up the seat belt tensioners using the centre touch pad , it always slightly tightened on switching on ignition, l will do a search for fuses , will also disconnect seat belt when in motion to see if warning comes on

 

[j200george]

Thank you , never seen this list before ,l believe l originally set up the seat belt tensioners using the centre touch pad , it always slightly tightened on switching on ignition, l will do a search for fuses , will also disconnect seat belt when in motion to see if warning comes on

What model year do you have carol?

 

[Carol]

Mine is 2018 AMG , l had all the extras with exception of heater , which l had post purchase