Fuel rail/system pressure too low

First of all, a warm hello to the community.

I'm glad that forums like this still exist despite all the social media platforms, and I'm happy to be a part of it.
As a diesel enthusiast, a diesel mechanic, and a general automotive mechanic, I hope that I can also contribute and be well-received here.

Okay, I have my first question regarding a customer's vehicle. Perhaps someone has encountered a similar problem before and knows what might be causing it.

It's a VW Sharan, manufactured in 2014, with a 2.0 TDI engine, 103 kW, and engine code CFFB.
The error code "P008700 Fuel Rail/System Pressure Too Low" reappears even after being cleared. As a result, the vehicle begins to stutter, according to the customer's complaint, and eventually enters a limp-home mode. After restarting, the engine check light will continue to illuminate, but the limp mode is not initially activated.

I've now instructed that the fuel filter be replaced, as it appears it has never been changed. This is the cheapest and quickest way to rule out that possibility.


What else do you think might be the cause? Perhaps it's the injector or the high-pressure pump? According to the error code, it seems there are recurring pressure fluctuations in the rail.

Thank you in advance.