Hi @ALXY_WANG1,
Some CMUs can be enabled by the MCU MCAL driver.
The driver calculates the thresholds automatically.

NXP provides the Safety Application Framework (SAF) for the S32K3xx series, which includes the following sCheck tests:
sCheck_CmuFcTest.c
sCheck_CmuFmTest.c
A development license for the full SAF version is available.
To obtain access please contact your NXP distributor.
Thank you,
Regards,
Daniel