Mercedes C Klasse Diesel Glow Plug Issue Resolved

That's a plausible diagnosis The glow control unit manages the glow plugs, which help start your diesel engine, especially in cold weather When they don't work, it can cause rough starts, smoke, and poor performance The engine light is triggered because the engine management system detects a fault A faulty cable or plug connection is a common cause, so your diagnostic test might be right Check the wiring to the glow control unit and glow plugs before assuming the unit is completely gone

What should I look for when I check the wiring Do I need special tools

When checking the wiring, look for frayed wires, corroded connectors, or loose connections Sometimes a visual inspection is enough You could use a multimeter to test the continuity of the wires, but if you're not comfortable with electrical testing, it might be best to have a professional take a look A proper diagnostic test at a workshop will pinpoint the exact problem However, you're probably on the right track with the glow plug system If it is the control unit, I'd guess around 95€ for the part

I checked the wiring, and everything seemed okay, so I took it to a workshop The glow control unit was indeed defective They replaced it, and now the preheating lamp is working normally, the engine light is off, and the smoke is gone Cost me 95€ for the part Really appreciate the help