[Sgt.Kanyo]

My parking sensors don't work. When you turn them, you can hear a loud, long beep and you see 2 bars on the displays.
Last time it had 3 bad sensors where 2 of them were faulty and 1 of them showed a broken wire. Broken wire has been fixed and the 2 faulty sensors have been replace, however the sensors still don't work. When we used the Mercedes STAR system to read for any error codes, it didn't give any, like last time. The parking sensor was an optional extra, not an aftermarket version.
Any idea what might be the problem?

 

[salman108]

Hello,

ALL the sensors have to be working fine for the system to work,
a single bad sensor renders the whole system useless.

some times, once you fix a particular sensor, you wake the devil in the rest of them.

A very easy way to check them is by pulse method.

Start the car, now place your finger ever so gently on the sensor.
You should be able to feel a slight pulse / tick sensation, which tells you that the sensor is fine.
You will have to engage the reverse gear to do the same with the rear sensors.

Once you check all the sensors to be fine, then suspicion moves to wiring and the PTS controller.

 

[Sgt.Kanyo]

Thank you very much for the reply. I'll try doing that. Like I mentioned the SDS didn't give any error codes unfortunately.

 

[Sgt.Kanyo]

Just tried that method, but I cannot feel anything. Tried it with engine on and tried it with ignition on, but nothing. Tried pushing it gently and also tried pushing it moderately.
Any other ideas? I mean it should give an error code if something is not working properly, right? Is there a way to reset the parking sensors?

 

[salman108]

Just tried that method, but I cannot feel anything. Tried it with engine on and tried it with ignition on, but nothing. Tried pushing it gently and also tried pushing it moderately.
Any other ideas? I mean it should give an error code if something is not working properly, right? Is there a way to reset the parking sensors?

Hello,
You don't have to push moderately or gently, just enough to touch.

It maybe that the actual module may have failed, It is located under the rear seat passenger side.

since the two error lights are coming on, this means that the module is getting power, and it is doing some thing.
use the SDS to try to go in the parktronic module. You can calibrate the distance warning in the module.

If SDS takes you to that screen, this would means the module is fine.
Else it may mean a big (main) break in the wiring.

 

[Sgt.Kanyo]

Thank you although I'm still surprised this isn't displayed in SDS. I'll try your idea and report back.

 

[Sgt.Kanyo]

Okay so we've tried accessing the parking module in SDS and it said "not present" or something like that. Does that mean that probably my parking sensor module is faulty? Also any tutorials on how to get to the module? I know it's under the rear seats at the passenger side, but I have no idea how to access it.