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Garmin G3X CAN Bus issue

paszekj

Member
I've been having issues with my G3X system recently (been flying close to a year with about 80 hours TT). I lost portions of the panel display shortly after takeoff (from Leadville, CO of all places). I climbed for a few minutes while debating whether I should land and everything returned to normal. I decided to return to my home airport (KCFO) and all was normal until it recurred while in the pattern at KCFO. My panel was built by Steinair who suspects that it's a loose connection somewhere in the CAN Bus. I've been pulling harnesses and inspecting them but have yet to find anything amiss.

I've been able to get it to occur a few more times while taxiing and have taken some videos and uploaded to a non-published YouTube channel for SteinAir to review. I believe the errors have been the same every time it's occurred. We're still troubleshooting but I thought it would be worth sharing links to a few of the YT videos just for everyone's information what it looks like. I certainly welcome any suggestions anyone might have.

I believe SteinAir has already been in contact with Garmin but I was hoping the Garmin folks would take a look and offer their thoughts. I will say that SteinAir's support has been excellent and they've reassured me they'll get it figured out and get it fixed. The question is do I feel comfortable flying it about 4 hours to their shop in MN? I feel like all the required instrumentation is there to be legal for VFR flight (between the PFD & MFD) as long as it doesn't act up in any way different than it has to this point. Here are links to a couple of the videos:

https://youtu.be/Rzdw7nKf0Hc

https://youtu.be/KoN2y69CpkE

https://youtu.be/4eJh4cwcf24
 
I feel like all the required instrumentation is there to be legal for VFR flight
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Well, since the required day-VFR instrumentation is zero, you’re correct.

What IMHO is not okay is what looks like a single-point failure: your G5 backup is losing airspeed data. When your main system fails is when the backup needs to work.
 
What IMHO is not okay is what looks like a single-point failure: your G5 backup is losing airspeed data. When your main system fails is when the backup needs to work.
Bob,

Why would you say that the G5 is losing airspeed data????

Steve
 
It seems you have a few different things going on. Are you sure you have the CAN bus terminated correctly? At a minimum it looks like your GEA24 and the GAD29 are having trouble communicating, but it seems you also have RS-232 communication problems. Those two things would seem to be separate issues since they are completely separate interfaces. It might be helpful to look at the order of CAN bus connections and see if you are loosing modules at a certain point on the bus. That might tell you where the the connection problem is if there is one. Since the CAN bus is daisy chained if you have a bad connection then the devices from that point onward on the bus will have trouble communicating.
 
Okay...I'm no expert but I had this same thing happen to me. As it turned out, it was software. It wasn't/didn't load correctly (probably a self induced error!)

I reloaded all the software and haven't had an issue since.
 
Check your grounds

I had a similar issue with an unstable CAN bus and it turned out to be a bad ground. If you used ring terminals make sure that any paint or removed and your have a clean connection. Ohm meter found the issue.
 
The first question is always: Was anything at all recently changed?

Another "I'm no expert" here, but the first thing I'd do for troubleshooting (on the ground) is turn off the G5 and bring it back up in config mode. Then see if the G5 tells you that you really are getting CAN bus network errors.

I don't have a G3X, but agree with another poster that the GAD29 and GEA24 are both involved in the errors, and so a software issue is a distinct possibility.

Please keep us posted. I hate that you're seeing issues, but I'm very interested in hearing the diagnosis and treatment.
 
Trust but verify . . .

Stein built my panel and harness as well - would certainly go back - but I did find 5 pins or sockets that were not fully locked. I pushed on very pin with a small dowel and pull it back until it locked if it moved. Same for sockets, but different tool.

They had tested the harness and it was fully functional at the "factory"
 
CAN Issues

I've been having issues with my G3X system recently (been flying close to a year with about 80 hours TT). I lost portions of the panel display shortly after takeoff (from Leadville, CO of all places). I climbed for a few minutes while debating whether I should land and everything returned to normal. I decided to return to my home airport (KCFO) and all was normal until it recurred while in the pattern at KCFO. My panel was built by Steinair who suspects that it's a loose connection somewhere in the CAN Bus. I've been pulling harnesses and inspecting them but have yet to find anything amiss.

I've been able to get it to occur a few more times while taxiing and have taken some videos and uploaded to a non-published YouTube channel for SteinAir to review. I believe the errors have been the same every time it's occurred. We're still troubleshooting but I thought it would be worth sharing links to a few of the YT videos just for everyone's information what it looks like. I certainly welcome any suggestions anyone might have.

I believe SteinAir has already been in contact with Garmin but I was hoping the Garmin folks would take a look and offer their thoughts. I will say that SteinAir's support has been excellent and they've reassured me they'll get it figured out and get it fixed. The question is do I feel comfortable flying it about 4 hours to their shop in MN? I feel like all the required instrumentation is there to be legal for VFR flight (between the PFD & MFD) as long as it doesn't act up in any way different than it has to this point. Here are links to a couple of the videos:

https://youtu.be/Rzdw7nKf0Hc

https://youtu.be/KoN2y69CpkE

https://youtu.be/4eJh4cwcf24

After reviewing the videos, it does appear to be a CAN bus failure. Of note, your PFD is still displaying your flight instruments, while the MFD is displaying the EIS information. That is because in addition to the primary means of communication between the various pieces of equipment that make up the G3X Touch system, the CAN bus, there is a second backup data path between the displays and those LRU's that provide critical information needed for flight (EIS and ADAHRS data).

We cant say for sure, but the behavior is indicative of an intermittent wiring problem, in which the CAN bus wiring is being shorted to ground. This can happen if the insulation on the CAN bus wire has been compromised, and a strand of the shield is making contact with the conductor.

It may be best to contact us at [email protected] (or 1-866-854-8433), so we can help walk through the troubleshooting process with you.

Thanks,

Justin
 
Shield

I had this same problem after I installed the G3X. To correct it I redid all the CAN Bus connections, taking special care with the shield (ground) connections to be sure they were encapsulated. Didn't find the "smoking gun" but the problem went away.
 
It’s easy to nick a wire with the blade when cutting away the insulation on a shielded twisted pair. The nick can intermittently make contact with the shield and cause problems on the CAN bus. I had a few to find and fix. Good luck!
 
John, I'm sure you will find the issue soon, it will be a bit of a pain, but just think about how awesome your panel is and you'll forget about it :D - seriously, beautiful panel sir. Good luck, I'm sure you will figure it out soon.
 
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