[ccjohnson]

On a side note: I had a bad chassis battery (couple of dead cells) I had to replace a while back. Went ahead & replaced both at the same time. Have had no CE/SE light issues since then. Not sure if the 2 are connected or not. But it did pop into my mind after seeing posts about a bad ground.

[77newell]

Since the sensors create a drop in voltage on the sensor line to the ECU, if the battery voltage is low there will be a sensor line that is the first to trigger a warning. The other sensors lines aren't quite there yet, as the battery voltage drops, someone will trigger first. This is where we need to put our thinking caps on. While the warning says, say, low coolant level, what it is really saying is: "Hey, I'm sensing low voltage over here, check it out". The interpretation of the voltage signal is usually right, but when it isn't we have to think about how the voltage could be low. One possibility is that the battery is low.

[NextNewell]

So to post a follow-up on this issue. After reading about the battery voltage possibly being the cause, I discovered that they were in fact low and once charged my Check engine light went away.
That is until I took it to Freightliner to have it checked out by an authorized Detroit Deisel shop for the new owner. Well, let me tell you that its was there 2 days and they could not figure out how to connect their diagnostic equipment, but yet they somehow knew that the coolant level sensor was an issue.  I talked to the assistant service manager and asked if they tested the sensor itself, and he told me, and I quote, " No, because we don't know if it's bad." 
I didn't quite understand that answer and I'm sure, after he said it, he must have realized how incompetent that answer sounded. This was Friday about 3:25pm and they wanted another day or two, not counting weekends, so they could continue their diagnostic ghost hunt. Now had I left it, they would've charged $940.00 just for diagnostic work. I declined but still had to pay $316.00 for two days of nothing. 
Had they just told me, or maybe I should have thought to ask,when I initially called on the phone, that their technicians don't have a lot of experience with the 8V92, I would have taken elsewhere. 

I told the new owner that unfortunately these engines come with one potential inconveinece: finding a competent mechanic that isn't retired.

[Fulltiming]

Apparently they didn't have the correct DDEC 2 reader or they could have read the error code that caused the Check Engine Light to come on. The correct reader will have the rectangular plug that matches what is under the dash on your coach. Trying to troubleshoot a Check Enging Light without the correct reader is a waste of time and money.