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Check engine soon and glow plug light stays on

1999 Mercedes Benz E-300 with 172K. While driving home the glow plug light just came on, soon after that the check engine soon light came on. Car rides fine and still starts good. What would be most likely reasons for these two lights to come on and stay on? Can I take my time and troubleshoot on my own or should I immediately take to dealer?

I would first make sure the alternator is working ok by having it tested. It may also help to know what code turned on the CEL light. Since the CEL light is on I wouldn’t wait very long to find out what is causing the trouble.

If you live in an area large enough to have a Mercedes dealer, surely there are many good independent shops that know Mercedes cars. They will almost surely fix it cheaper than the dealer.

That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here. 

You have a diesel right?