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davidsaxby · 09-22-2012, 04:50 PM

i have a 2005 monaco, holiday rambler with a Cummins isb-300.
I am having problems with the check engine light on and the trans light on while driving. Sometimes the check engine light will go off on its own as well as the trans light. Trans is allison 2500mh.
I took it too cummis and they found a code 241. "lead to change oem harness"
I took it to allison and their codes are U0073, ""CAN Bus reset counter Overrun" the next code is U0100 "Loost CAN Communication with ECM
The allison tech at the shop I took it to said he had a similar problem and he replaced a plug to the ecm eith a new pigtail and everthing worked O.K.
Anyone have any ideas?????????
Dave

Skip426 · 09-22-2012, 06:05 PM

Bad connection, somewhere, and you can get a lot of grey hairs trying to track this kind of thing down. Before replacing , and if not tried already, remove and reseat the connection and see if that's any help. Using an electronic connection cleaner spray may help too. Kind of hard to track down when the Engine Control Module and the Trans Control Module seem to be blameing each other.

Tony Lee · 09-22-2012, 06:06 PM

Have you tried disconnecting and reconnecting the harness connectors a few times - but wouldn't one of the two techs you paid for advice have come up with some practical suggestions.

Websurfer · 09-22-2012, 06:14 PM

Quote:

Originally Posted by davidsaxby

i have a 2005 monaco, holiday rambler with a Cummins isb-300.
I am having problems with the check engine light on and the trans light on while driving. Sometimes the check engine light will go off on its own as well as the trans light. Trans is allison 2500mh.
I took it too cummis and they found a code 241. "lead to change oem harness"
I took it to allison and their codes are U0073, ""CAN Bus reset counter Overrun" the next code is U0100 "Loost CAN Communication with ECM
The allison tech at the shop I took it to said he had a similar problem and he replaced a plug to the ecm eith a new pigtail and everthing worked O.K.
Anyone have any ideas?????????
Dave

I had practibly the same problem with my Pace Arrow. Turned ou to be a bad ground connection on the chassic.(One of 14)

davidsaxby · 09-23-2012, 12:13 PM

skip,
The cumminms guys used a cleaner but the problem still is the same>
any other thoughts ??????????????
One of the three responses i got so far might be worth looking into which is a bad ground which would sure make a possible solution from "websurfer" who was the third response

Skip426 · 09-23-2012, 03:45 PM

Anything you can check/clean yourself , has to be worth the effort. Did the Cummins guy do both the Cummins & Allison control unit connectors ?
Did the Allison tech, have that connector off? or spray it ?
Since I retired, I don't have access to the digagnostic flow charts that are produced for each of these codes. I will be into the shop where I used to work in 2 weeks, moved from the town, and see if I can still get in from there. One big problem I have is every manufacturer has his own set of acromyms; ECM, can mean Engine Control Module or Electronic Control Module, or something else; Dodge, used Engine CM, and Transmission CM.
I would check all the grounds, around the engine bay in particular, check all the connections between the trans and the main harness, the Allison control Module and the harness and any connector you can find between the Allison & Cummins control modules. You may end up back at the Allison shop for the pigtail, but at least you've eliminated some other possibilities. Good Luck.