I get an error code each time I start the engine. The code is "J1939 Data Link Abnormal Update". The engine is a 2001 Cat 3126B in a 2001.5 Fleetwood Discovery. The code seems generic and I'd like to find a more definitive description of the problem. Jim

Submitted by Art on Mon, 2015-01-19 09:59

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Hello Jim We're not really engine specialists; more like nerdy Armchair Warriors when it comes to real specific diag codes. We can guess--and some things we can help with the logic or general meaning. Issues like this one are more on the guessing side. That disclaimer being said; I googled this: "J1939 Data Link Abnormal Update" -with quotes. Only a few returns came back. Please understand also that while the engine model and use are very different, the code-is-the-code. It carries principally the same meaning, cross platform. The more reliable one can be followed by way of the link below: http://cariinfo.pe.hu/look/Peterbilt_Code_J1939/Caterpillar__Annoying_SAE_J1939_DATA_LINK__Online_Community/aHR0cDovL2ZvcnVtcy5jYXQuY29tL3Q1L1Bvd2VyLUdlbmVyYXRpb24tUHJvZHVjdC9hbm5veWluZy1TQUUtSjE5MzktREFUQS1MSU5LL3RkLXAvMTEyNw==_blog Its a link...though indirectly...to the CAT forum where these things are commonly discussed. Makes sense, its their code. The forum is members-only and so explaining the indirect route. If I follow the line of of solutions correctly, it seems there may be: -- damage to the J1939 data bus. [Done any mechanical changes recently; heavy rain/ snow adventures?] -or- -- An ECU problem, perhaps programming. If no service had been done and no extreme weather [water/salt damage] were part of the picture...and if it were me and my really nice coach, I'd get the flashlight, make sure the JIB data cable (to the data bus) were firmly connected. I'd check any place I or staff have recently been working or servicing. Look for where there may be exposed data-bus cabling or where it could collect water or a stray rock. Check the various other data connections around the bath/sink area (leaks?)...like that... Once the low-hanging fruit were picked, then it means a trip to the CAT dealer or your favorite service center for a deeper look. Keep us posted here on the results; knowledge IS horsepower! Art Renda Documentation Central, Silverleaf Electronics (888) 741-0259