Cat mpd

[hmason]

Need some help. We had a really bad rain and lightning storm last week. After the storm passed we learned that a boat behind our slip experienced a lightning strike. I decided to test our electronics and all was fine. RADAR, depth sounder, chart plotter etc. all work perfectly.

Next I started the engines; twin CAT 3406e. They started right up, however the engine computer displays (MPDs) at the helm(s) had an error code "J1939 Data Communications Loss." There are 4 displays; one for each engine in the pilothouse and also on the flybridge. All are displaying the same error codes.

I called my CAT mechanic. He connected his computer directly to the engine ECMs and determined that they are outputting all the required data and are acting normally. We cannot find the fix for the error codes at the MPDs. I assume that it is something common to all the displays. Thoughts please.

Thanks in advance for your input. Howard

 

[Alaskan Sea-Duction]

NEMA 2000 comm failure?

 

[hmason]

Link won’t open

 

[pacopico]

J1939 in the controller area network (CAN) data bus that the ECM and MPD's communicate on. If the CAT ET connected to the ECM and the tech noted that the CAN Bus was active and transmitting then it is most likely a physical layer issue (wiring, terminating resistor, other controller causing a fault, etc.).

You will need a tech that can troubleshoot the whole system.

 

[O C Diver]

The way I read that code:

"Communications loss"

It's saying it momentarily lost Communications with the computer to let you know that the event happened.

Seems to me there should be a reset in the display menu to cancel / reset the warning code. This is like a service warning light on your car, the dealer resets it after he does the mileage based service.

Ted

 

[High Wire]

Try powering down and back up. Somewhere there is a separate power supply to the NMEA 2000 bus.

 

[O C Diver]

I'm wondering if disconnecting the engine battery and then reconnecting reboots the engine computer and both the computer and the displays see everything as normal and loose the error code. Have done that more than once with boat electronics with head scratching success.

Ted

 

[hmason]

I’ve tried that. Message still appears. I’ve powered off everything, all battery switches, shore power, inverter etc.

 

[High Wire]

Maybe the NMEA bus fuse is blown?

 

[twistedtree]

The J1939 bus is NOT the N2K bus, though they may be connected with a converter. Are your engines tied into N2K for monitoring on Maretron or your MFDs? If so, I’d start by locating and disconnecting those converters.

Next try unplugging the CAT displays one at a time and see if the problem goes away. You might have one display that took a hit and is trashing communications for all of them.

Keep in mind that the two engines and 4 displays may be one J1939 bus, or each engine could each have their own with their two displays. I don’t know how Cat does it. But since you have all 4 displays showing the same problem, my guess is that they are all on one bus, and one device is blocking coms.

 

[vacser]

That happened once on my CAT C-12. I turned the key, got in a hurry and pushed the start button. Same code. The proper procedure is to turn on your key, wait 10 to 15 seconds for the ECM to load, then start your engine. I have had no problems in 4 years. Good luck

 

[sunchaser]

HM
Three things if simple suggests on TF fail:
- post same question on boat diesel
- the 3406s are wonderful engines and getting a savvy tech on your support contacts would be a good step
- Tim Caruso, a great Cat guy in FL could point you to the right tech help.