Also, DCN shows CN board is online and communicating, listed as MAINCOP1.

Car Fault: 1084
Fault Description:

Car is too far out of level for a Relevel - Homelift requires a BP zone.

Possible Causes:

An invalid configuration or adjustment

Corrupted memory - Install previously downloaded backup copy of non-volatile memory (this file was previously generated: Service>Transfer>Download from IMS)

A bad CPU card

SPI Loop Error is for a LON! Most Tac50-04's are CAN.

Sorry didn't check for typo...its a 1085 fault.

Car Fault: 1085
Fault Description:
TAC50-04/32bit - An SPI Error has been detected on a CN or HN Node.

Possible Causes:

For hall nodes - Use the DHN(F/R) command to determine the HN node ID (the first failed node will display)

For car nodes - Use the DCN command to determine the CN node ID (the first failed node will display)

Check all wiring and connections at the failing node

Invalid configuration - See the DCN and DHN commands and verify that the port numbers are correct

Issue the TECC command to make sure all of the nodes are configured

A bad CN, HN, or L24 board

What all is in the loop? If it’s all S24-1 boards, get one and replace each, one at a time. Also, how did you verify the cables are good? Most plug in testers will only catch a bad cable that’s actually open. Replacing them is the best way to be sure. I made a little tester with 2 breakout boards that jumps the pairs together on one end so you can check resistance of each loop from the other. Those kind of bad cables usually show up as one loop measures 1 or 2 tenths of an ohm more than the other 3. And you did the TECC after replacing the CN right? It doesn’t know how many ports to look for until you do.

Had this once, Perform teccr first that erases all prior configurations then do tecc then tecf for front and tecr for rear.

You have to do the TECF/TECR before the TECC. TECCR, TECF/R TECC