2011 Mercedes Sprinter P0671 Glow Plug Circuit Error - Hard Starting at Cold Temperatures
Hi everyone, I own a 2011 Mercedes Sprinter and recently encountered Diagnostic Code P0671, which indicates a glow plug circuit fault on cylinder 1. This issue occurred after I left the van parked at an airport for several days during a trip when outdoor temperatures dropped to -30°C. When attempting to start the vehicle, it would crank but fail to ignite. I replaced all glow plugs with original Mercedes OEM parts, which temporarily resolved the P0671 code. However, the vehicle still struggles to start on the first attempt—often requiring between 2 and 6 tries—and this issue is most noticeable when temperatures fall below -1°C. I took it back to a repair shop where they replaced the battery, fuel filter, and the glow plug module. While no error codes are now appearing, the starting difficulty persists under cold conditions. Could anyone provide insight into what might be causing this? Any experience with similar issues on 2011 Sprinter models? Thanks in advance for your help.
Hello! Could you please share the vehicle's mileage and exact model variant (e.g., 2011 Mercedes Sprinter 2500, 3500)? I recommend checking fuel pressure during startup using live data. For proper engine ignition, fuel pressure must reach at least 150 bar (15 MPa or 15,000 kPa). If the pressure only reaches between 70–120 bar—just slightly below the required level—it may indicate a faulty fuel injector. If pressure is significantly low, possible causes include a failing high-pressure pump, a leak in the fuel lift pump or front cylinder head fuel lines (common on older models like 2006). While I'm not certain if this applies to the 2011 Sprinter model, some versions feature an electric fuel pump located in the tank—this could be relevant. It's worth verifying whether your vehicle has such a setup.