mbp

Hi,

2011 GL350 diesel just had an engine light on yesterday. I took to it to a shop for scanning and these codes show up. The shop cleared the code and it came back today.

15FC00 The learned value for component B28/8 (Differential pressure sensor (DPF)) are outside the permissable range.
15FF00 The signal voltage of component B28/8 (DPF Differential pressure sensor) is too low

Can anyone tell what cause this fault code to show up? To fix it, is it something DIY? I've done some research but didn't found much information.
Also, I'm kind of worry if the car still safe to drive? What should I look out for if I need to keep driving temporary? It seems to ride fine as of now. No sign of trouble yet.