DAve, according to the service manual there are a few possibilities
Sud - SUDS LOCK (Overdose of Detergent detected during the Wash Cycle)
The motor control unit senses a suds lock condition by analyzing the current draw on the drive motor. If “Sud” is displayed a potential suds lock is detected. This may signify a bad pump, an extra heavy load, excessive detergent, or excessive suds.
• If too much detergent was used, run the unit through a Rinse/ Spin cycle then a Normal cycle without adding any detergent. This should clear the unit of the excess detergent.
• Check the drain hose and make sure it is not plugged or kinked
• Check Wire Harness connections to the Drain Pump, Pressure Switch, and Central Control Unit (CCU)
• Check/ Clean Drain Pump Filter of foreign objects
• Check Drain Pump
• Check the Pressure Switch
• Check CCU
To make your job easier, try to download the manual from here. Good luck and I hope it helps.
I had the same problem. I did two things: 1) Clean your drain from the wall all the way inside the machine to the drain pump. This will take some time, a star screw driver, and some large mouth pliers. use the pliers to loosen the hoses on the outside and inside of your machine. I used my hose pipe to wash the clogs and debris out. I was amazed at how much junk came out. Put all the hoses back together. 2) Take off the bottom front panel (3 screws). You will see the drain pump and a large circular screw. This is your drain filter. Unscrew it, clean and replace. This should take care of your problem.