Power everything down one at a time, and restart with a laptop hooked up. It should so a system confidence test. See if it says all is ok.

We were getting this fault code often . Oddly enough group of three and it was car number two. Ours would drop the calls and passengers would think they were stuck. It would restart on its own after about 30 seconds. Check communication wiring and shields. We were leaning to the CPU board, and of course you have to replace the CPU board in all three. One day the power supply failed on car number two, we replaced it and along with the DSP back up battery (on all three)and we have not had the complaint or the fault show up yet. That was about two months ago. Might just be coincidence,....and I am holding my breath now that I am typing this.

Did you check the ripple on the PS1 power supply? Replace it if there is more than .010 vac. If all your confidence tests are a GO and you’ve already cleaned your card connections, try unplugging the load weigher J4.

Make sure your wiring looks like this:

https://www.dropbox.com/s/10jcfhw7ofvvyd0/Group%20Comm%20Wiring.pdf?dl=0

Thanks for the replies and the wiring diagram as well, heading to the job now. Solid that sounds exactly like what is going on with our job, to the T. I will let you guys know how it turns out. Thanks for the info. Ill check the confidence tests and the PS1 power supply today, Ill keep you posted. Thanks everyone

This issue has started to come back up again. We replaced the PS1 and it ran fine for one month. Started right back again. I am confident that it is a PS issue as if we adjust the voltage a little low, this code pops up on a constant basis. We can adjust it higher (12.6 and 5.6) and it will run for a few days and comes back. The only thing PS1 feeds is the DSP. The input voltage feeds all the other Power supplies. So I do not think it is a noise issue on the input side. We did put a surge protector on just the PS1 and that did not help. Unless someone has another idea, I believe we are going to send the DSP off for repair.

Does this car with the 16 error problem have a separate group controller or integrated group control?

The CPU and I think the PMI cards use that 5v supply too. Make sure the card cage fan is working and ALL of your contactors have suppressors.

It has integrated group control, will check suppressors.

Can put this one to bed. Voltage Monitor contacts 11 and 14 feed all four power supplies. Replaced Voltage Monitor and problem as not come back. Luckily we were there and the monitor was dropping in and out on us.

I’ve got a group of 5 T4 passenger cars, 10 stops each, car 3 is down for a repair, but all other cars are getting a fault 16 and the status on IMS says DISP LOSS about every other run and was getting them before car 3 went down. After about 3-5 seconds of the status saying DISP LOSS each car will reset itself and continue to run except cars 2&5 are starting to fault out and not want to reset itself after so many resets. It used to happen intermittently and the cars would all go into emergency dispatching but I sent the CPU for car 1 off for repair and then the fault went away for almost a year. It’s starting to come back with a vengeance now and I’m not sure where to start again. The cars are not yet going into emergency dispatching but I’m sure it is coming in the near future. Very high profile customer that doesn’t like down elevators if you catch my drift. I’ve changed the back up batteries, changed my voltage monitors, reseated all my boards, checked my power supplies, and checked my daisy chain wiring for my group. Really hard to pinpoint where my issue is coming from. Any help would be greatly appreciated.

If this customer was serious about not liking their elevators down, they would've already modded a couple of them and plan on the other three after the first 2 are done.

Anyhow, I'm not an expert on T4s, worked on a 4 bank of them a bit. I would start by trying to narrow down your issue to a car. Can you take a car out of the group at a time to narrow down which car might be causing your issue? I don't know how they are interconnected if you can completely pull one, or maybe just shut one car off and see if the problem continues or stops

Gentlemen, is there any update on this situation or progress? I’m having almost the exact same issue.