VelSatis Fuel Filter Heater Fault

Those symptoms strongly suggest a fuel filter heater circuit problem. The ECU probably detects the heater's absence, triggering the error and affecting engine performance. Reduced power and response are from the ECU compensating for perceived cold fuel, leading to bad combustion. Higher fuel use and uneven idling are further results. Have you checked the fuel filter heater relay and wiring for corrosion, damage, or loose connections?

Thanks for the quick reply. I've looked at the relay and wiring, but I don't have the tools for a proper continuity test. Can you explain how to confirm the fuel filter heater circuit is working before I replace anything?

Given your tools, it's best to see a qualified technician. A multimeter can check continuity, but a real diagnosis often needs equipment like an oscilloscope to see the signal and load response of the fuel filter heater circuit under different conditions. Forcing a fix without proof can cost more than a proper diagnosis.

Thanks for the advice. I booked it into a workshop. They found a bad connection to the fuel filter heater, replaced the harness and plug, and the problems are gone. The repair cost 95€. Thanks again for your help.