Cruise Control - Bucking - ECM

[bigfish]

Had a situation occur recently with the cruise control. The ECM was reprogrammed to latest revision to eliminate a "J1939 DATA LINK ERROR" that kept cropping up in the Silverleaf diagnostic histogram. Mark Harrah indicated this was a normal issue with some 2005 coaches. The fix was to have a Cummins shop reprogram the engine ECM to latest update. The ECM program was updated to version W90026.27. The result was severe bucking whenever the cruise was set and speed was at steady state, bucking would stop if accelerating, decelerating or shutting off the cruise. Siverleaf histogram indicated "ECM Power Loss". Because of earlier thread on this forum by Sully & Rick with a similar problem, I recognized that the fault may be in the program and not a hardware problem (loose gnd connections, etc) and was able to advise tech of same. There was a fault code FC285. After discussion with Cummins RS, they advised tech that one of the parameters in the ECM program is for "Transmission Type". This parameter was found set to "Manual" instead of "Automatic" in the latest rev's for this coach. Changing the parameter to "Automatic" resolved the bucking problem.
BTF

[bigfish]

Had a situation occur recently with the cruise control. The ECM was reprogrammed to latest revision to eliminate a "J1939 DATA LINK ERROR" that kept cropping up in the Silverleaf diagnostic histogram. Mark Harrah indicated this was a normal issue with some 2005 coaches. The fix was to have a Cummins shop reprogram the engine ECM to latest update. The ECM program was updated to version W90026.27. The result was severe bucking whenever the cruise was set and speed was at steady state, bucking would stop if accelerating, decelerating or shutting off the cruise. Siverleaf histogram indicated "ECM Power Loss". Because of earlier thread on this forum by Sully & Rick with a similar problem, I recognized that the fault may be in the program and not a hardware problem (loose gnd connections, etc) and was able to advise tech of same. There was a fault code FC285. After discussion with Cummins RS, they advised tech that one of the parameters in the ECM program is for "Transmission Type". This parameter was found set to "Manual" instead of "Automatic" in the latest rev's for this coach. Changing the parameter to "Automatic" resolved the bucking problem.
BTF

[Paul "Sully" Sullivan]

Posted September 17, 2006 11:14 PM
As I reported earlier, we have had a bucking problem when cresting a hill while driving with Cruise Control engaged. After several stops at Cummins, and calls to WRV we were told in Anchorage that Cummins had a patch that would be ready by the end of September. We are at Coach Care Denver and they downloaded the patch to the ECM, and we now have a functioning CC.

Thanks to all who made suggestions,

Sully


This is a problem we had w/our '05, if you call Mike Young at Cummins Yakima he can give you the Cummins Service Bulletin # for the patch.

[Rick Coleman]

Earlier this year I reported on a previous thread that when using my cruise I would get a severe vibration or bucking as if I was going over freeway expansion joints to the extent I could not use my cruise. I went to Cummins to have the ECM patch installed, which was supposed to cure the symptom. It didn't do a thing, so I still have the problem and can't use my cruise.

[Dale777]

Rick Coleman,

I had the bucking when using cruise control going over a crest until Cummins in Nashville, TN updated the ECM module. Now it works perfectly. So, I know at least some Cummins dealers know what to do.

[bigfish]

Rick,
I suggest you get back to a Cummins Coach Care facility sometime and have them contact Cummins Rapid Service about the cruise control issue. Cummins RS may want the techs to e-mail them a mirror image of your ECM program and after review they will probably be able to advise the Coach Care tech on what action to take. If it is the same problem as mine, all they will need do is change the parameter "Transmission Type" from "Manual" to "Automatic". It's at the top on page 11 of the mirror image. If this resolves the problem, Cummins should pick up the tab.
BTF

[Rick Coleman]

Thanks for the suggestions. I will give it a try.