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Re: help - dead along road

Reply #25 –
Kent is quite correct that any problem with the engine or transmission can be quickly diagnosed if it has a computer controlled engine and transmission. Not only does it make driving almost idiot proof but cuts the emissions considerably.

An all mechanical engine/transmission/air suspension RV does give a bit more piece of mind, especially for those of us that might be off the beaten path and a long way from help. But, as Dave said, these failures are few and far between. Reading about them does effect the confidence a little though. Another reason to know exactly what ECU you have. Actually, if the part number is known ahead of time, a very reasonably priced spare can usually be found on ebay, etc. But then, you could fill the cargo bins with spares.

The problem here is most of the computer controls were designed for fleet work where a bus or trucking company could send out a repair truck and would also have the necessary parts in stock to quickly get the rig back on the road again. Nice to have a support team like that.

I would like to see the next generation of RVs have computers with a separate "limp home" mode so while the engine or transmission might no longer be operating at it's best, it could be driven a reasonable distance to a repair facility and not leave a family stuck by the side of the road. Many current cars have this already. Perhaps I am a bit behind the times and some have this now.
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: help - dead along road

Reply #26 –
I believe most computer controls have emergency systems as part of the programming.  If a component of the system is not operating properly, the computer stores a code describing the failure, and if possible we drive on.  If proper operation of the component is critical, the computer protects the transmission from having us stupidly destroy it.

Anyone else know more about this?

In my case, the ECU itself failed catastrophically.  It smells like smoke and has parts rattling around inside.  A new one was $2800 with tax, which might discourage some from carrying spares.

oldMattB
Matt B
1998 u-320

Re: help - dead along road

Reply #27 –
Quote from: oldmattb –
I believe most computer controls have emergency systems as part of the programming.  If a component of the system is not operating properly, the computer stores a code describing the failure, and if possible we drive on.  If proper operation of the component is critical, the computer protects the transmission from having us stupidly destroy it.

Anyone else know more about this? ...
We experienced the "emergency systems as part of the programming" for the ECU on the transmission of our previous coach.

While driving in blizzard conditions, the Allison MD3060 transmission on our SOB coach went into "limp" mode. We could operate in 1st, 2nd, and reverse gear only. We were able to get to a safe place to park. Coach-Net helped us interpret stored codes as "loss of speed sensor." After weather conditions improved overnight, I was able to go under the coach and reattach a connector that had been pulled apart from the weight of accumulated ice.

We bought the FT to replace the SOB so that we can "hunker down" and wait for a blizzard to pass. In the SOB coach, we chose to flee to warmer conditions because the SOB coach could not protect us from the cold.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX