04A

Explanation
A time-of-day (TOD) clock on one of the central
processors is in error. The clock must be set to avoid generating
a machine check later in nucleus initialization program (NIP) processing.

System action
Every central processor with a clock that needs
setting will enter restartable wait state X'04A'.

Operator response
Perform restart function, then press the TOD
ENABLE and ALT keys at the system console to set the clock. IPL will
continue.

Source
Nucleus initialization program (NIP)