[DON]

I believe your “EGR” valve is not functioning smoothly, thus sticking .

Install a Ugly Fix and all will be cured.

AL

[Marshall]

The first thing I would ask is what were you doing when it went off?

When I first got my DDECV I threw a few lights that said Check at next stop and when you recycle the key it’s gone, no code nothing. I found whenever it went off I was working the motor harder than normal.

My transmission was set to manually downshift and if I got in a pull and operated the motor at what Detroit says is the power curve and let it pull down to 1300 RPM where the motor is what I call in a dead zone meaning you are on the throttle and you can’t increase speed and your hanging onto 1300 RPM the motor is dead I would throw a light. Out west driving above 4000 ft all day and the motor sucking air that is thin it happens alot. I’ve got calls from some guys that were trying to operate in the lower RPM range and you can’t do it when you are working the motor hard.

If you want to drive at 1400 to 1600 around most of this country your fine but if you are working the motor you have to get the RPM’s up. I never let my old bus get below 1500 RPM without dropping a gear if I was in hilly or mountain terrain. It never happened again the last 5 years I owned it.

I’ve discussed this at length with Prevost and all the coaches come out setup to operate at it’s best fuel economy and shift parameters are set for this. My current coach I had to change many things in Parameters to get it to operate where I wanted it.

When I sold the DDECV the buyer who now is a good friend sent a I quote Professional driver to pick it up. The buyer called me and was angry, he said the driver thru an engine light going up Parly out of SLC. I told him to tell the driver don’t lug it you have to operate it at 1500 to 1800 RPM or more when you are working it.

Sorry for the long winded post but I’ve had friends call me more than a few times that have had this happen.

Later

bv

[Chuck & Katrina]

Bernie,

Thanks for your thoughts. I haven’t found any correlation to activity and seeing the error. The last time it came on, I simply cycled the power (without starting the coach) and it came on. It has not cleared (error still in the DID) since with a dozen or so start cycles.

I highly suspect it has something to do with EGR. That’s a longer conversation. I have an Ugly Fix that I took off about a year ago…..maybe I’ll throw that back on and see what happens.

My Bluefire device doesn’t see any codes. I have access to another code reader. I’ll try that as well. The performance of the coach is still very good, just have that annoying message in the DID (without Red CEL or Yellow CEL).

I would love to see a listing of what conditions cause a error message. Again, no Yellow CEL or Red CEL. Just the error in the Drivers Information Display.

---

2000 Featherlite H3-45

2024 Jeep Grand Cherokee

Leesburg, FL

[M Keith]

The only other thing related to the EGR would be the Delta P sensor. That would give you a light and no loss of power.

You should be able to see that with a reader.

Later

bv

[Marshall]

I want to add to Bernie’s advice and comments.

First, I think he has hit the nail on the head. But if we as drivers do not want to actually have to be troubled by having to exercise our brain as drivers, we can use the tools Prevost has provided to make our lives simple.

All of our coaches are set for economy. But if we always drive in the economy mode in the transmission then we need to manually do some occasional downshifting to avoid climbing a hill lugging the engine. It is not a big deal to push the down arrow when at the bottom of a hill and then we we are at the top pushing the big D on the transmission pad, but if we do not want to be bothered the transmission pad has a button to push for performance mode.

In normal economy mode the transmission factory program causes early upshifts and delayed downshifts which is exactly what Bernie points out is not such a good thing. Putting the coach in performance mode cures that problem, It will downshift sooner to keep the revs up, and it will upshift later to prevent engine lugging.

Start every trip by pushing the performance mode button and the engine and transmission will work together to keep the engine in the sweet spot and not in a situation where it will lug.

Drive it like you stole it.

[Archived]

I appreciate the advice, but not the case this time. I routinely drive in Performance mode and did so for an extended time just before shutting down. I then turned on the ignition without starting the engine and the error appeared. I am very suspicious it is something to do with checks the ECM does when you turn on the ignition….

Also, I drove it about 3 hours one day and 3 hours back the next day (both in Economy and Performance mode) and the error did not clear. I’ve looked, but have not found the conditions that cause a “Check engine at next stop” error.

[Dick]

Possibly coolant level?

[Tom]

Well….the mystery is solved. It’s the dreaded SIC 412 code. Which is low voltage on the Real Time Clock (RTC) battery. Basically the battery back-up that’s inside the ECU. Only impacts the DDEC IV and DDEC V ECU’s.

I’m handy with a soldering iron and the replacement looks fairly straight forward. Just need to find a 2 volt lithium battery with solder leads. Another option looks to be a re-programming by Detroit Diesel that kills the error code. Not sure if you need to replace the battery or not.

When the fail, the batteries are prone to leaking their acid which spills out on the PC board and starts to etch solder lands that it shouldn’t. Sounds like the best approach is to replace the battery. They are spec’d for a 10 year life. Mine is 15 years old.

Does anyone know where the ECU is located on a 2007 H3?