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jrusselltx · 04-19-2018, 08:22 PM

Seems the main data bus in my Knight has gone totally haywire. The transmission throws a data bus error as does the ABS system. The code reader cannot read the J1939 (higher speed, newer) data at all. The slower J1587/1708 data that the Alladin uses seems OK.

Putting an oscilloscope on the test connector at the engine or in the front left bay shows the same screwy waveforms. Does anyone know of a repair facility in the Indianapolis area that is competent to trouble shoot this? It's more than I can tackle. It's an ISC engine, Allison 3000 transmission, and Eaton/Bendix ABS system.

theroc · 04-19-2018, 11:43 PM

A few years ago, we were staying for about a week in the Indianapolis area and both of our neighbors at the park we were staying at were having mechanical issues. They told us some of the locals they talked to recommended this shop and both were very pleased with the service.

Indy Mobile Auto and Truck Repair in Avon (not very far from the airport).

Indy Mobile Auto & Truck Repair - Home

9255 E US Hwy 36
Avon, IN 46123

(888) 959-8350

Google reviews

Even though they have mobile service, you can also have work done at their shop. They have several mechanics that supposedly very good at diagnosing diesel pusher RV issues. They do a lot of repairs and maintenance on commercial semis.

We only had them do an oil change so can't really comment on their diagnostic ability but everybody at the shop seemed very nice and accommodating.

We keep a log of places around the country that are good or bad when we either hear it by word-of-mouth or experience it personally.

TheJanieLynn · 04-20-2018, 02:35 AM

Why not take it to Crosspoint Cummins. They're expensive, but they got state of the art diagnostic equipment. They also send you a daily report on their progress by e-mail. I had heavy duty engine work done there on my ISC 350, paid dearly, but was pleased with the final result.

jrusselltx · 04-21-2018, 06:46 AM

Actually, I did take it there. They offered (over the phone when I was asking if they could do the work) to read the codes for free, and then evaluate if they could work on the problem. They only do engine (and generator) work and would not work on the problem unless it was the engine itself.

Ironically, I had spent some time the day before looking at the electrical signals on the 9 pin connector at the engine. The signals on the bus are not correct for the type of bus used, so I was skeptical if any "code reader" could decode the data. This particular connector was just dangling loose on its cable, which is a really bad idea on how to put a cable together and it should never have left the factory that way, but that's another story. In any case, the connector was right beside the fill pipe for the transmission which is solid and well restrained, so I tie wrapped the connector to it for strain relief.

When I started the coach, I had NO data warnings from the transmission or ABS. And the dash speedometer was working again. Cummins read the codes and had one diagnostic error message which the tech said he had seen before recently, that it was not a Cummins code, and their tech people could not identify where it came from. Everything worked OK again on the return trip (about 10 miles each way) so it is "fixed" at least for now. Next step is to see if I can find out what damage to the wiring has been done from the connector flopping around for the last 10 years.