EML, NOx sensor repeated faults

[MattyJ]

Help please?
I have a 2015 diesel C class and for the last 18 months the engine management light (EML/MIL) has come on 6 times.

First the adblue wiring loom was replaced, now the Merc garage just keep changing Nox sensors but after a few weeks/months the light comes back on again, and they change another sensor.
So far replaced 3 upstream, 2 downstream NOX sensors and the wiring harness.

I have no confidence the fault won't come back.

Any help appreciated please??

Here are some of the codes I got from the garage if it helps.
Thank you

Fault codes first repair:
P229F-85 NOx sensor 2 cyl bank 1 has a malfunction there is a signal above the permissible limit value
P1BC3-00 additional fault freeze frame data for fault analysis (data set 03)
P20EE-84 the efficiency of the SCR catalytic convertor (cyl bank 1 is not sufficient there is a signal below permissible limit value
U029E-02 Communication with NOx sensor 2 has a malfunction

Fault codes 2nd repair:
P229E11 NOx sensor 2 cyl bank 1electrical short to ground
P229E13 NOx sensor 2 cyl bank 1 electrical short open circuit
P220F77 NOx sensor 2 heater sensor fault commander position can't be reached
P229F08 NOx sensor 2 malfunction signal
P229F17 NOx sensor 2 limit value for voltage exceeded

 

[dry run]

I'm tempted to ask what Merc garage your using? I think I would have lost faith in them a while ago.

 

[MattyJ]

I'm tempted to ask what Merc garage your using? I think I would have lost faith in them a while ago.

I have! Which is why I am posting here and hope someone has had similar issues - and found a fix....

 

[Wighty]

I have! Which is why I am posting here and hope someone has had similar issues - and found a fix....

Well if it’s a Merc garage of some form using Star diagnostic stuff it would seem they are having difficulty fixing it , you may need to accept that changing garages may not lead to a permanent fix . Adblue cars do seem to cause a lot of problems on the forum .
Have you considered trading the car in ?