[NextNewell]

Took the coach out for a quick trip this week and 10 min into the drive the yellow check engine light came on. All the gauges read normal and we were only driving about 50 miles, so I just kept an eye on things. 
When I started up the next day, the yellow light stayed on.  But then as we drove slowly to the park exit, I didn't notice the red light had also came on until after the engine shut down as we were stopping at a stop sign. I used the override switch to startup and move to a safe location. While moving the yellow light came on/off then both yellow and red came on but after we stopped both light turned off. So after sitting there idling for a bit with both lights off, I figured we continue driving. Well we got about a mile and both yellow and red came back on so I pulled off the road on to the shoulder. 
What I did was disconnect a plug and one of the wire harness' plugged into the DDEC, turn the ignition key on/off, then reconnected both to the DDEC. Why I thought about doing that, I don't know, but by coincidence or other, it did allow us to get home with just the yellow light on.
Any ideas?

[ccjohnson]

Get the codes read & then you will have an idea what you are dealing with. We have been having issues with our CE & SE lights coming on and codes say low coolant level. Coolant level is fine and replaced sending unit. Next is replace coolant level wiring to DDEC. Until I get a chance to get it in we just hit override to reset & keep going. I do have a Silverleaf digital on a laptop so I can keep n eye on temps & pressures. Stewart & Stevenson is hoping it is just wire issue & not a DDEC issue.

[RussWhite]

I am not alone I see.

I just had my experience with low coolant level alarm. Replaced the sensor and went for a while, and got it again.
Annoying as the level was fine, but coach power got derated about 50% and no cruise. I limped on to my destination.

I started at the sensor end and first remade all the connections on the common side. My final connection to the chassis was above the voltage isolator in the rear electrical cabinet. It's hard to see, but up there. Also redid the grounds on the main battery cables and the one on the rail outside the electrical cabinet. Nothing I found gave me the feeling I had taken care of the root problem.
I had researched the DDEC wiring and knew the connector and pin as well as wire number and color involved. Well, it must have been my lucky day as the only pin with obvious corrosion on the Vehicle Connector ( front side of ECM on the bottom ) was position H3 - low coolant.

A nice wash with contact cleaner on both socket and pin and back together and problem solved. Your mileage as always may vary. Russ

[NextNewell]

Are there any suggestions for an OBD I or II Code Reader? And 6 or 9 pin for the Silver Leaf system?

[ccjohnson]

Let the folks at Silverleaf know what you have under dash for a connection. I believe you should have the rectangular plug instead of the round plug. They were pretty good with tech support when we got ours. The was an issue with ours that required sending it back for repair when we first got it. They were really good talking us through process of getting settings the way we wanted and owners manual is pretty good. Will take you a bit of time to get it up and running the way you want it. With older coaches like ours, there are a lot of features that don't work like trans temp, gear indicator etc.. But overall I would hate to be without ours after using it for a while. The fuel consumption is almost to the quart on 220 gal of fuel burn .

[NextNewell]

Well, thanks to the SilverLeaf program, I now know what is causing the check engine light to come on, but I'm not having any luck finding a resolution to fix the problem.

[ccjohnson]

Have had same issue with ours. S&S is supposed to rewire harness, but have not had it back on in several months now. I did see a post on here saying that the issue was in corroded pins on DDEC. After cleaning problem resolved itself. I am thinking that may be same with mine so not sure if I will have S&S rewire now.

[ccjohnson]

We did have S&S clear codes off DDEC a while back. Only had CE & SE on once since then.

[Richard]

I would be looking at the coolant sensor on the tank that feeds the radiator. Check the connections.

[RussWhite]

I will follow up a bit with my experience. The pin associated with coolant low was clearly corroded and all others looked new. I have no explanation for that. As I mentioned earlier, I cleaned it up and it was fine for a while. But, it came back. So, I ordered new sockets and replaced the corroded one. I think the real issue, once I got a close look at the old socket, was it had lost its spring tension and was not pressing against the rectangular pin.
Another option you have is to ground that socket. The coolant level sensor pulls the ECM voltage low when coolant is present, but does not pull it all the way to zero. I confirmed this by installing a test wire on the coolant level low wire at the ECM. Grounding might solve your problem ( although you give up the level low alarm ) until you can deal with it. Changing the socket was not easy. The correct extraction tool and crimping tool would have helped, but I did without.
Another difference is the reaction of DDEC IV to coolant low. My coach goes into a reduced power mode, no cruise, but does not turn on the engine shutdown light and does not shutdown. This, to me, seems like a more rational thing to do than a shutdown. If coolant is really low, one can watch the temperature like a hawk and get coolant added before any damage is done.