The check engine warning pops up right after starting with the "Engine Electrical" in the display and the glow plug light comes back on. Does this know if a glow plug is bad or what is it? Starts and runs fine.

Sounds like you have at least one bad glow plug. Disconnect the cable at the glow plug relay and check ohms between ground and each pin (individual glow plug circuit). The glow plug that has a skewed reading will be the one that needs to be replaced. Remove intake and swap out gp to fix. Remove gp with engine hot and after you have sprayed it with Kroil or something similar. Take your time removing it. I've had some come out in a matter of minutes and others take an hour to back out.

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Jim

I have the tooling needed to remove a stuck glow plug in a OM606, let me know if you need it.

OM606 glow plug change - one broke off

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Thanks-if it is just a glow plug I will have to get busy and get the 97 running first.