U13 indicates that a Panasonic FR1 cannot spin. Check the load distribution and the support before interpreting the stop as a motor fault.
The FR1 family chart assigns U13 to that stage. Capacity and recovery should match the equipment manual.
What to check when it stops
When the drum is still and the door releases, untangle any caught-up clothes and redistribute a load concentrated on one side. If there is only one very absorbent item, check that the cycle and the garment are compatible; forcing it to spin does not necessarily solve the balance issue.
Do not add clothes as a routine step to a full drum. The allowed weight depends on the cycle and the type of fabric. Resume with the sequence outlined in the manual, without increasing the spin speed to override the protection.
If it happens with different loads, check the support of the stopped machine and whether it rocks. If the problem persists with a balanced load and correct support, technical inspection is needed. U13 does not identify bearings, suspension, or the motor separately.
Note the laundry composition and whether U13 repeats with a typical load; this will help distinguish normal use from a recurring issue.