Check Engine light in front driver's bay

[Sebulba]

Hello all,

I noticed something today that, well, raised a concern.  Not sure there is really a problem, but....

I happened to open the front driver's side bay to get something and I noticed a red light was on that I never noticed before.  It says "check engine".

What I do know:
We had a good drive from Santa Fe, NM up her to West Yellowstone, almost 1000 miles.

We have benn parked for about 35 days, no engine starts in this time.

About 3 days ago I put a Noci Genius 5x2 on the bus batteries.
After I put this in it diagnosed one battery as being week, so I ran the battery repair function on that battery.  Then I got to thinking that maybe I should switch the main disconnect while repais was running, so I did connected that.

Not sure if any of these things are related, just trying to give you any info that may help

Thanks in advance for your attention to this.

Seb

[Sebulba]

Just to the left of the light is what looks like a pushbutton switch that says "check engine switch".  I haven't pushed it. 

Does anyone know what these are for or do?

Thanks

[Iceni John]

When you start the engine, do the SEL and CEL both come on for a few seconds then both go out, or does one or both stay on?   Can you flash out any active codes using the CEL?

Some years ago I had the ECM completely disconnected from the start batteries when the main battery disconnect was Off, and it caused no end of problems.   I would get the CEL and even the SEL flashing on for a second or two while driving, but no codes were being set, and all operating parameters were normal.   When I restored the Constant-On feed to the ECM when the batteries are switched Off, no more weird phantom lights.   Maybe your NOCO charger is affecting the ECM when it's on the Repair setting  -  is the NOCO giving a higher than normal voltage, or an intermittent pulse, or what?   Is it similar to a Desulfate setting on a charger or charge controller?   I think the ECMs are sensitive to "dirty" or non-constant power feeds.

John   

[Sebulba]

When you start the engine, do the SEL and CEL both come on for a few seconds then both go out, or does one or both stay on?   Can you flash out any active codes using the CEL?

Some years ago I had the ECM completely disconnected from the start batteries when the main battery disconnect was Off, and it caused no end of problems.   I would get the CEL and even the SEL flashing on for a second or two while driving, but no codes were being set, and all operating parameters were normal.   When I restored the Constant-On feed to the ECM when the batteries are switched Off, no more weird phantom lights.   Maybe your NOCO charger is affecting the ECM when it's on the Repair setting  -  is the NOCO giving a higher than normal voltage, or an intermittent pulse, or what?   Is it similar to a Desulfate setting on a charger or charge controller?   I think the ECMs are sensitive to "dirty" or non-constant power feeds.

John

Hello John,

Thank you for your reply.  In hindsight, I do need to make sure to disconnect when I let the charger do it's repair thing, since it may use some out of specs voltages or ampurages.

Sorry for not replying sooner, with work, a good old fashioned cold and the snow and cold weather we had after I did the original post,it took a while to get back to this.

Anyway, I wanted to move the bus back about 10 feet, since the snow bank that was here a month ago is now gone, so I fired her up and all worked well.  After I was done doing that I checked the light was no longer on, so I guess I was concerned for nothing.

Till the next problem ....

Seb