A Klasse diesel preheating light issue

That sounds familiar! I had almost the same thing happen with my A Klasse diesel. Engine light was on, preheating light wouldn't go off, and cold starts were rough, with engine misfires. For me, it was the glow plugs. Did you check all the glow plugs, or just assume it's one? Because sometimes when one goes, the others aren't far behind. Glow plugs preheat the cylinders for better engine combustion, especially in a diesel engine. When they fail, especially in cold weather, you get those engine misfires.

Thank you for your swift response. I have not yet individually tested each glow plug. My assumption was based solely on the error code retrieved from the diagnostic scan. Given your experience, would you advise testing each glow plug individually prior to replacement? Is there a specific methodology you would recommend for this testing procedure?

I'm no expert, but based on what happened to me, just replace them all. It's going to cost a bit more upfront, but think of the labor costs if you only replace one now and another goes bad next month! Plus, at that mileage, they're probably all getting tired. Seriously, get it done. And unless you're super confident, I'd let a workshop handle it. Messing with those things can be a pain, and you don't want to strip anything. It's not worth the hassle!

I appreciate your counsel. I have elected to follow your recommendation and have entrusted the vehicle to a reputable workshop for a comprehensive glow plug replacement. Your insights regarding the potential for recurring failures and the complexities of the replacement procedure were persuasive. Thank you again for your assistance.