Help needed… Radar/Sensor issues W205 C220D (65 Plate)

[bob mushroom]

Travelling in March 2020 (2 days before lockdown) my car lost power and all sensors became operative. I drove to destination and on return all worked again until I got the warning Active Blind Spot Assist inoperative.

This would come on/stay off intermittently along with PRE-SAFE functions limited see owners manual.

In July the Active Blind Spot assist inoperative was always on. In September my Distronic started to intermittently become inoperative along with the lane keeping assist, until know in December both are always inoperative.

I have had my car serviced in November and a diagnostic done which said fault Radar 3 great……

The problem is the garage do not know which radar 3 is…. Can anyone help? I do not want all bumpers off and labour costs rising on a hunt!

I am suspicious of what the fault may be though with the intermittent on/off and the apparent daisy chain of failures.

I know it will cost money to fix but I want to know all cheaper than full replacement avenues have been explored

Fuses?
Wiring?
Sensor check?

Can anyone offer any suggestions to help the car perform as it should?

Thanks in advance

 

[malcolm E53 AMG]

Probably a good place to start would be to clean and check all the sensors:

http://www.mercedesmedic.com/mercedes-radar-sensor-problems-solutions/

The bumper may need to be be removed to check the position of the two front sensors behind for alignment

Codes need to be read on STAR if all the sensors check out it might be something as simple as a software update or a control module

Has the car had a wheel alignment done prior to the faults appearing if so the radar may need recalibration?

Hope this helps!

 

[bob mushroom]

Thanks fro the reply. When the Merc Indy did a diagnostic I assumed it would be STAR. Are there alternatives?

No wheel alignment before but recalibration of radar is something I haven't considered

 

[bob mushroom]

Looks like I will have to bite the bullet and pay for mb to find then replace whatever it is....

 

[ajlsl600]

If yr keeping car and have interest to learn to resolve.get yrself a decent code reader icarsoft v2 or a cloned star xentry.it WILL save u much more than cost.often once u get a code many can help on here.
These cars are just to complex (often deliberately so ) its that or 100 each time BEFORE you know issue.
Failing that yr lookin a decent indy.easily found on here. .if u must go benz dealer ask on here for satisfied people before you choose dealer.many only interested in yr cc!

 

[bob mushroom]

If yr keeping car and have interest to learn to resolve.get yrself a decent code reader icarsoft v2 or a cloned star xentry.it WILL save u much more than cost.often once u get a code many can help on here.
These cars are just to complex (often deliberately so ) its that or 100 each time BEFORE you know issue.
Failing that yr lookin a decent indy.easily found on here. .if u must go benz dealer ask on here for satisfied people before you choose dealer.many only interested in yr cc!

Having taken it a indy their diagnostic only advised RADAR 3 fault - they were unable to state which RADAR 3 is. This is my concern as there seems to be a daisy chain of faults over a few months. Is anyone able to shed any light on RADAR 3?

 

[ajlsl600]

They should be able to tell u the actual code that would likely help with diagnostic advise on here. Rader 3 ??

 

[alexanderfoti]

An indy with Xentry will narrow which sensor it is pretty quickly.............................

 

[RooJayC]

@bob mushroom did you ever narrow down the catalyst to these issues. My 2016 c class has begun to do exactly the same thing.

presafe alert
Blind spot inoperative
Lane assist inoperative
Distronitic inoperative

everything I’ve seen across the internet is suggesting the radar sensor.

 

[MarinB17]

@bob mushroom @RooJayC did either of you resolve this? I have the same on my active blind spot and dist+ equipped 204

 

[RooJayC]

@bob mushroom @RooJayC did either of you resolve this? I have the same on my active blind spot and dist+ equipped 204

@MarinB17 I’ve not resolved mine yet. The independent merc specialists I use have been unable to narrow down the issue. Have you had any solutions offered to you yet?

 

[V6Matty]

I had this on my 212 very recently, it normally appeared after the car had sat for a few days so initially it seemed like a low battery issue (voltage was low even though it cranked fine), Mercedes really don’t like low voltage and it makes them do some very strange things at times because the power on test usually gets wrong information. Anyway that seemed to sort it out for a while, then it happened again, this time it was after only a few hours, discovered a spider had decided to make a very sticky web across the face of the radar sensor, was a paint to get it all cleaned off on the 212 as access is rather tight. This worked and had presafe and distronic back, but would occasionally still loose the blind spot assist, that eventually then became permanently disabled. More digging and eventually with my Indy we tracked it back to water ingress to the rear bumper radar £470 for a new one (plus fitting and coding) and finally all back to normal.

 

[RooJayC]

Damn… another pricy fix. Thank you though. All roads seem to lead back to the radar which makes sense as everything that’s not working is linked to the car detecting it’s surroundings

 

[V6Matty]

Damn… another pricy fix. Thank you though. All roads seem to lead back to the radar which makes sense as everything that’s not working is linked to the car detecting it’s surroundings

There is more that one radar, plus as it was water ingress in mine it may be that getting the connections off and giving them a good clean and spray with a contact cleaner it may bring things back to life?

 

[RooJayC]

thank you bud good shout. Isn’t it bumpers off to access the radars?

 

[V6Matty]

thank you bud good shout. Isn’t it bumpers off to access the radars?

It’s easier with the bumper off as the space is a little limited in there, not too difficult to get them off though and probably a DIY job if you have the space at home