S212 C155E13 - The pressure relief valve for system pressure has a malfunction. There is an open circuit.

[BlueRubber]

Hi all,

Got a facelift S212 E350 2013, about 20 days ago had an inde mobile mechanic replace the rear passenger suspension airbag with an OEM unit.
Today when starting the car it came up with this fault:
C155E13 - The pressure relief valve for system pressure has a malfunction. There is an open circuit.
It also has an amber image on the dashboard showing the car with an arrow under it.

It's probably coincidental, but it happened when I started the car to plug in the scan tool.

What are the diagnosis steps to take to figure out the fix?

Thanks

 

[malcolm E53 AMG]

Airmatic systems rely on the air pump so first thing to check is that the compressor runs it is situated underneath the car at the rear it has its own cover panel you should hear the compressor kick in when the car is started and as you’ve already had an airbag fail there is a possibility that the pump was overloaded and burnt out. If the compressor doesn’t run check the fuse first and then the relay for the compressor which can be found in the near side rear boot compartment there is a small cut out trim to lift to access it. I carry a spare relay in the car they are only a £10 item from the dealer.

 

[BlueRubber]

From some more research, it seems this is likely a broken wire near the connector for the pressure relief valve.